UNIVERSITY  OF  CALIFORNIA 
AT   LOS  ANGELES 


MKMOIRS 


OB*   THE 


TORREY  BOTANICAL  CLUB. 


VOL.  III.  No.  2. 


THE  NAI ADAGES 


NORTH   AMERICA. 


BY  THOMAS  MORONG. 


(PLATES  XX-LXXIV.) 


ISSUED  MARCH  15,  1893. 


PRICE,        -       ---        $2.00. 


• 

MEMOIRS 


OF  THE 


TORREY  BOTANICAL  CLUB. 


No.  2. 


The  Naiadacese  of  North  America, 

BY  THOMAS  MORONG. 

(PLATES    XX.— LXXIV.) 

The  first  botanist  to  reduce  the  North  American  species  of 
Potauwgcton  to  anything  like  a  complete  and  intelligible  sys- 
tematic  shape  was  Dr.  J.  \V.  Robbins,  of  Uxbridge,  Mass.  To 
his  pen  is  due  the  description  in  Gray's  Manual,  edition  5,  of  the 
species  within  the  range  of  that  work.  To  this  he  added  in  the 
Botany  of  King's  Expedition  an  account  of  the  species  found  in 
Nevada,  Utah  and  the  adjoining  regions,  completing  his  work  in 
the  Botany  of  California  by  Brewer  and  Watson  by  a  determina- 
tion  of  the  species  on  the  Pacific  coast  which  were  then  known. 
At  his  death,  in  1875,  Dr.  Robbins  bequeathed  to  me  his  collec- 
tions, containing  not  only  the  gatherings  of  many  years  by  his 
own  hand,  but  also  specimens  from  the  Herbarium  of  Tuckerman, 
one  of  the  earliest  students  of  this  genus,  and  from  Oakes,  his 
close  friend  and  collaborator,  in  whose  lamented  early  death  our 
country  lost  one  of  its  most  promising  naturalists.  Dr.  Robbins 
left  with  his  Herbarium  an  injunction  that  his  plants  should  be  dis- 
tributed as  widely  as  possible.  I  feel,  therefore,  that  I  am  execu- 
ting a  sacred  trust  in  issuing  a  monograph  upon  the  Order  that 
includes  as  its  principal  part  the  family  upon  which  my  friend  ex- 
pended so  much  thought.  Besides  this,  the  paper  here  presented 
includes  not  only  the  embodiment  of  my  friend's  most  cherished 
convictions,  but  the  results  of  my  own  studies  in  a  personal  ex- 
ploration of  nearly  all  the  waters  from  Quebec  to  Virginia,  and 
from  the  Atlantic  to  the  Mississippi.  This  monograph,  however, 

271983 


would  have  been  impossible,  at  least  in  its  present  form,  except 
for  the  assistance  of  friendly  European  botanists  to  whom  I  am 
indebted  for  large  suites  of  specimens  and  invaluable  counsel. 
With  Mr.  Arthur  Bennett,  of  Croydon,  England,  distinguished  for 
his  extensive  acquaintance  with  Potamogcton  forms  in  all  parts  of 
the  world,  and  for  his  contributions  to  the  literature  of  the  subject, 
I  have  enjoyed  a  correspondence  covering  the  last  twelve  years, 
and  during  the  course  of  that  time  have  received  from  him  speci- 
mens of  Naias,Zanic1iellia,  Ruppia,  Zostera  and  Potamogcton,  which 
represent  nearly  all  the  species  of  these  families  known  to  Euro- 
pean Herbaria.  His  generous  assistance  has  not  ended  here,  but 
he  has  examined  for  me  the  materials  at  Kew,  the  London  Mu- 
seum of  Natural  History,  Berlin  and  the  Herbarium  of  Linnaeus, 
so  that  I  feel  as  well  acquainted  with  these  great  collections  as  if 
I  had  visited  them  in  person.  I  am  also  much  beholden  to  that 
acute  botanist  of  Cambridgeshire,  England,  Mr.  Alfred  Fryer,  for 
beautiful  specimens  of  the  various  interesting  forms  of  Potamo- 
geton  which  occur  in  the  fens  about  Chatteris,  and  for  many 
original  and  discriminating  analyses.  Elegant  specimens  of  the 
Northern  Scandinavian  forms  have  been  contributed  by  Dr.  Gustaf 
Tiselius,  of  Stockholm,  than  whom  no  one  is  a  better  judge  of  the 
Continental  species  of  Potamogeton.  The  late  Prof.  Caspary,  of 
Konigsburg,  Prussia,  was  another  of  my  European  correspon- 
dents, from  whom  was  received  many  valuable  specimens.  The 
collections  of  the  Harvard  Herbarium,  of  Columbia  College,  the 
Academy  of  Sciences  at  Philadelphia,  and  at  the  National  Her- 
barium at  Washington  have  been  freely  submitted  for  examina- 
tion, as  well  as  the  large  private  collections  of  Mr.  Canby,  of 
Wilmington,  Delaware,  I.  C.  Martindale,  of  Camden,  New  Jersey, 
and  others.  Indeed,  I  may  say  that  there  is  scarcely  a  collector  of 
pond  weeds  in  the  country  with  whom  I  have  not  at  one  time  or 
other  held  correspondence,  and  from  whom  I  have  not  received 
specimens.  And  yet,  notwithstanding  these  advantages  for  a  wide 
comparison  and  a  close  study  of  this  group  of  plants,  so  protean 
are  their  forms,  so  eccentric  their  action,  constantly  changing 
under  changed  conditions  of  season  and  water,  that  I  put  forth 
this  treatise  with  great  diffidence,  and  feel  that  the  subject  is  very 
far  from  being  exhausted 


3 

The  Naiadaceae  arc  for  the  most  part  strictly  aquatic  plants, 
arising  from  long,  sometimes  nodose,  rhizomes.  Two  of  the 
genera  now  included  in  the  order,  Triglochin  and  ScIicucJizcria, 
are  inhabitants  of  bogs  and  marshes;  while  another,  Lilcea,  usu- 
ally begins  its  life  under  water,  but  continues  to  grow  in  the  mud 
after  its  native  water  has  subsided.  Triglochin  and  Lilcea  bear 
their  inflorescence  on  scapes,  the  remainder  on  branching  and 
leafy  stems.  The  aquatics  are  normally  submerged  plants,  but 
some  of  the  Potamogeton  family  bear  two  kinds  of  leaves,  floating 
and  submerged.  The  leaves  are  properly  sheathing  at  the  base, 
and  this  appears  in  all  the  genera,  except  in  some  species  of  Pota- 
mogcton.  Even  these,  however,  as  in  the  group  of  which  P.  pec- 
t  in  a  fits  may  be  considered  as  the  type,  the  so-called  stipule  is  adnate 
to  the  base  of  the  leaf  and  forms  with  it  a  sheath,  produced  at  its 
extremity  into  a  sort  of  ligule.  In  the  other  species  this  organ, 
though,  for  want  of  a  better  name,  it  is  termed  a  stipule,  is  much 
more  in  the  nature  of  a  spathe  that  at  first  encloses  the  young 
buds,  remaining  afterwards  at  the  base  of  the  elongated  nodes, 
petioles  and  peduncles  as  an  appendage  which  soon  decays.  In 
Zostcra  and  PJiyllospadix  the  spathaceous  character  is  still  more 
developed  as  the  flowers  are  borne  on  true  spadices  contained  in 
a  foliaceous  sheath  or  spathe.  Flowers  perfect,  monoecious  or 
dioecious,  either  naked,  tubular,  or  with  a  perianth  of  4  to  6  dis- 
tinct herbaceous  segments.  Stamens  I  to  6,  occasionally  more, 
distinct  and  hypogynous  in  the  perfect  flowers,  solitary  or  connate 
in  the  unisexual,  with  extrorse  i-2-celled  anthers.  Ovaries  I 
to  6,  distinct  or  rarely  connate,  I -celled;  containing  in  our 
North  American  species,  with  few  exceptions,  a  single  ovule. 
Fruit,  various;  capsular,  follicular  or  drupaceous.  The  fruit  in  the 
Zostcrc(e  is  usually  termed  an  utricle,  but,  while  having  a  mem- 
branaceous  pericarp,  it  is  frequently,  at  least,  if  not  always,  dehis- 
cent. Seed  straight  or  curved;  the  embryo  corresponding,  ortho- 
tropous,  anatropous  or  campylotropous,  without  albumen. 

From  this  brief  characterization  it  will  be  seen  that  the  order  is 
composed  of  several  heterogeneous  groups.  With  the  exception 
of  the  Juncagineae  and  Lilaeae  the  order  is  a  natural  one.  These 
two  groups  have  long  hovered  between  Alismaceae,  Aroideae  and 
Naiadaceae,  with  all  of  which  they  are  more  or  less  closely  allied, 


and  yet  they  are  really  distinct  from  either,  and  a  rigid  classifica- 
tion would  certainly  follow  the  arrangement  of  Micheli  in  D.  C. 
Mon.  Phan.,  and  constitute  each  of  them  a  separate  order.  Lilcea 
is  anomalous,  and  quite  as  distinct  from  the  Juncagineae  as  the 
latter  are  from  Naiadaceae.  There  is  an  advantage,  however,  in 
placing  closely  allied  groups  under  one  order,  if  possible,  and  I 
therefore  follow  essentially  the  arrangement  of  Bentham  and 
Hooker. 

Sub-order  I.     JUHCAGINCJE. 

Marsh  plants  with  rush-like  leaves.  Flowers  spicate  or  race- 
mose, perfect.  Perianth  4-6-parted;  segments  in  two  series. 
Stamens  3-6.  Carpels  3  or  6,  i-2-ovuled,  more  or  less  united 
while  immature,  dehiscent  or  indehiscent.  Seeds  anatropous,  em- 
bryo straight. 

1.  TRIGLOCHIN. 

Flowers  ebracteate,  racemose.  Perianth  segments  3  or  6. 
Carpels  3  or  6,  united  until  maturity.  Leaves  all  radical. 

2.  SCHEUCHZERIA. 

Flowers  bracteate,  racemose.  Perianth  segments  6.  Stamens 
6.  Carpels  3,  distinct,  stem  leafy,  rush-like;  fruit  a  follicle. 

Sub-order  II.     I.II.AI-M:. 

Marsh  plants  with  cylindrical  leaves.  Flowers  dimorphous, 
solitary  and  in  spikes,  monoecious.  Perianth  none  or  a  single 
bract.  Stamen  I,  ovary  I,  ovule  I,  anatropous.  Carpels  indehis- 
cent. 

3.  LILAEA.  Flowers  monoecious,  the  pistillate  naked  at  the 
base  of  the  leaves,  with  very  long  styles,  or  in  close  spikes  on 
scapes;  the  staminate  in  close  spikes,  on  scapes,  under  a  single 
bract.  Carpel  I,  I -seeded. 

Sub-order  III.     x  A I  Vl>i:.i,. 

Immersed  aquatics  with  flat  leaves.  Flowers  variously  ar- 
ranged, perfect,  monoecious  or  dioecious.  Perianth  of  4  segments, 
or  a  mere  hyaline  envelope.  Ovaries  solitary  or  distinct,  i-ovuled. 
Carpels  rarely  dehiscent.  Embryo  curved  or  straight. 

£  Potameae. 

Flowers  spicate,  perfect,  bractless.  Perianth  of  4  segments  or 
none.  Stamens  4  or  2.  Carpels  separate,  I -seeded;  seeds  cam- 
pylotropous.  Embryo  curved. 


4-    POTAMOGETON. 

Perianth  segments  4.     Carpels  sessile. 

5.  RUPPIA. 

Perianth  none.     Carpels  long-stipitate.     Fruit  in  umbels. 

§    Zannichelliae. 

Flowers  axillary.  Perianth  none  or  hyaline.  Stamen  I  with 
elongated  filament,  or  of  2  or  3  connate,  sessile  anthers.  Ovaries 
2-9,  i-ovuled;  ovules  pendulous  from  the  top  of  the  cell,  ortho- 
tropous. 

6.  /AXXICHELLIA. 

Perianth  none.  Stamen  I ,  with  a  short  filament.  Carpels  2-9, 
a  little  curved.  Fruit  in  umbels. 

§  Kaiae. 

Flowers  monoecious  or  dioecious,  axillary.  Perianth  a  hyaline 
envelope.  Stamens  of  I  sessile  or  2  connate  anthers.  Ovaries 
solitary,  i-ovuled;  ovules  anatropous.  Embryo  oblong. 

7.  \AIAS. 

Flowers  solitary  or  glomerate. 

§   Zostereae. 

Marine  plants  with  long  linear  leaves.  Flowers  monoecious 
or  dioecious,  on  an  enclosed  spadix.  Perianth  none.  Ovaries  I, 
sessile,  i-ovuled;  ovules  pendulous,  orthotropous.  Embryo 
straight. 

8.  ZOSTER  A. 

Flowers  monoecious.     Carpels  ovoid. 

9.  PHVLLOSPAIMX. 

Flowers  dioecious.     Carpels  heart-shaped. 

i.  TRIGLOCHIN,  L.  Sp.  PI.  338  (1753). 
Marsh  plants  with  radical,  semiterete,  fleshy  leaves,  which  have 
membranous,  often  ligulate,  sheaths  at  the  base.  Flowers  per- 
fect, in  spikes  or  racemes,  on  long,  smooth,  naked  scapes.  Seg- 
ments of  the  perianth  3-6,  concave,  the  3  inner  inserted  higher 
than  the  others.  Stamens  3-6 ;  anthers  2-celled,  s.essile  or  nearly 
so,  inserted  at  the  base  of  the  segments  and  attached  by  the  back, 
extrorse  and  with  the  segments  deciduous.  Ovaries  6,  united  or 


rarely  free,  I -celled,  sometimes  partially  or  wholly  abortive  ;  ovules 
solitary,  basilar,  erect,  anatropous ;  style  short  or  often  wanting; 
stigmas  as  many  as  the  ovaries,  plumose.  Fruit  of  3-6  cylindra- 
ceous,  oblong  or  obovoid  carpels,  which  are  distinct  or  connate, 
coriaceous,  costate,  when  ripe  separating  from  the  base  upward  from 
a  persistent  central  axis,  the  tips  straight  or  recurved,  dehiscing 
by  a  ventral  suture.  Seeds  erect,  cylindraceous  or  ovoid-oblong, 
compressed  or  angular.  Embryo  conformed  to  the  seeds. 

The  carpels  often  appear  indehiscent  in  the  dried  specimens, 
but  they  are  all  furnished  with  a  distinct  internal  carinated  suture 
which  it  may  need  moisture  to  open.  The  species  have  a  rush- 
like  appearance,  and  are  generally  found  upon  saline  marshes  near 
the  seashore  or  inland,  and  often,  also,  in  fresh  water  bogs  and 
marshes.  The  long,  linear  leaves  are  usually  erect,  sheathing  each 
other  and  the  scape  at  the  base,  often  partially  buried  in  the  earth. 

Authors  vary  much  as  to  the  number  of  species,  Kunth  enu- 
merating 1 6,  which  Micheli  reduces  to  9.  They  are  widespread, 
inhabiting  the  frigid  and  temperate  zones  of  both  hemispheres. 

Three  species  only  occur  in  North  America. 

Carpels  3. 

Fruit  linear  or  clavate,  tapering  to  a  subulate  base.  I.    T.  palustris, 

Fruit  globose.  2.    T.  striata. 

Carpels  6. 

Fruit  oblong  or  ovate,  obtuse  at  base.  3.   T.  maritima. 

i.  TRIGLOCHIN  PALUSTRIS,  L.  Sp.  PI.  338  (1753). 
Perennial.  Rhizome  short,  oblique,  throwing  out  radical  fibres 
and  slender,  fugacious  stolons.  Leaves  narrowly  linear,  shorter 
than  the  scapes,  5-12  inches  long,  tapering  to  a  sharp  point; 
ligule  very  short.  Scapes  1-2  from  the  same  rootstock,  very 
slender,  striate,  8-20  inches  high.  Racemes  5-12  inches  in  length; 
pedicels  capillary,  in  fruit  erect-appressed  and  2^-3^  lines  long. 
Perianth  segments  6,  greenish-yellow,  ovate  or  roundish,  in  2 
series,  the  inner  a  little  higher.  Anthers  6,  sessile,  in  2  series, 
each  under  a  perianth  segment,  large,  yellow.  Ovaries  of  3 
united  carpels  and  as  many  cells  and  ovules ;  stigmas  as  many  as 
the  carpels,  sessile,  plumose.  Fruit  3-3^  lines  long,  slender, 
linear  or  clavate,  tapering  into  a  base  scarcely  thicker  than  the 
pedicel  and  tipped  with  3  short  recurved  points.  Ripe  carpels 


cylindrical,  tapering  at  base  into  a  sharp  hair-like  termination, 
separating  upwardly  from  the  axis,  and  hanging  suspended  from 
its  apex ;  central  axis  3-winged.  Seeds  loose  in  the  carpels, 
straight,  the  raphe  marked  by  a  purple  line. 

This  species  is  readily  recognized  by  its  very  slender,  erect 
scapes,  and  its  racemes  of  slender,  erect,  club-shaped  and  long  cap- 
illary pedicels. 

It  grows  in  boggy  places  or  sometimes  in  slightly  wet  grounds, 
or  in  moist  sands  by  brooksides  and  brackish  pools  and  ponds. 
I  found  it  quite  abundant  near  the  Niagara  Falls  on  the  Canada  side. 
It  also  occurs  at  various  localities  in  Western  New  York,  and  thence 
westward  to  Montana  (Belt  River  Canyon,  Williams)  and  north- 
ward through  Canada  from  New  Brunswick  to  Alaska  (Macoun). 
Common  in  the  British  Islands  and  throughout  Europe  and 
Northern  Asia.  (Plate  XX,  with  a  ripe  fruit  magnified.) 

2.  TRIGLOCHIX  STRIATA,  R.  and  P.  Fl.  Peruv.  iii.  72  (1802). 

T.  triandra,  MX.  Fl.  i.  208  (1803). 

Small  perennials  from  upright  or  oblique,  stoloniferous  root- 
stocks.  Scapes  i  or  2  from  the  same  rhizome,  more  or  less  angu- 
lar, usually  not  over  10  inches  high,  but  sometimes  reaching  an  al- 
titude of  14  inches.  Leaves  slender,  slightly  fleshy,  nearly  or 
quite  as  long  as  the  scapes  and  ^-i  line  in  width.  Flowers  very 
small,  light  yellow  or  greenish,  in  spikes  or  racemes,  with  pedicels 
only  Y2~y\  line  long,  not  increasing  in  fruit,  the  spikes  1-5  inches 
in  length.  Perianth  segments  3  ;  stamens  3,  oval,  large.  Ovaries 

3,  united,   crowned  with  long   plumose  stigmas.     Fruit  globose, 
y±-\  line  in  diameter,  appearing  3-winged  when  dry  by  the  con- 
traction of  the  carpels.    Carpels   3,   coriaceous,  rounded  and    3- 
ribbed    on   the    back.     Central    column    broadly    3-winged,    the 
wings  composed  of  a  thin  membrane  with  a  strong  rib-like  border. 
Seeds  loose,  slightly  curved,  the  raphe  inconspicuous. 

Our  species  belong  to  the  form  called  robustior  by  Micheli. 
Two  other  smaller  and  more  slender  forms  are  described,  named 
JUifolia  and  hninilis,  the  former  from  the  Pacific  islands  and  the 
latter  from  Chile. 

7.  striata  seems  to  take  the  place  of  our  other  species  in  the 
Southern  States,  occurring  along  the  seaboard  from  Maryland  to 


8 

Louisiana  in  salt  and  fresh  water  marshes.     A   widely   diffused 
species,  native  not  only  of  the  United  States,  but  also  of  Brazil, 
Chile,  many  of  the  Pacific  Islands  and  Southern  Africa.     (Plate 
XXI,  with  a  ripe  fruit  magnified.) 
3.  TRIGLOCHIN  MARITIMA,  L.  Sp.  PL  339  (1753). 

T.  Mexicana,  H.  B.  K.  Nov.  Gen.,  i.  244  (1815). 

T.  data,  Nutt.  Gen.  i.  237  (1818). 

T.  maritime* ,  var.  data,  A..  Gray,  Man.  Ed.  2,  437  (1852). 

A  perennial  plant  with  a  long,  unstoloniferous,  often  sub- 
ligneous,  rootstock,  and  a  thick  caudex  which  is  usually  covered 
with  the  sheaths  of  old  leaves.  Scapes  stout,  nearly  terete,  striate, 
12  to  24  inches  high,  commonly  solitary.  Leaves  much  shorter 
than  the  scapes,  fleshy,  semi-cylindrical,  striate,  tapering  gradually 
to  a  long  acute  or  obtuse  point.  The  leaves  are  usually  about  i 
line  broad,  but  sometimes,  as  in  a  specimen  collected  in  California 
by  Dr.  Bigelow,  on  Lieut.  Whipple's  expedition,  reaching  a  width 
of  nearly  2*^  lines.  Flowers  very  numerous,  often  densely  crowded 
on  the  scape,  and  even  appearing  verticillate  at  times.  The  ra- 
cemes often  reach  a  length  of  40  cm.  or  more;  pedicels  decurrent, 
i  to  i  y2  lines  long,  slightly  increasing  in  fruit.  Perianth  seg- 
ments, 6,  the  3  interior  smaller,  ovate  and  greenish-white,  each  sub- 
tending a  large  sessile  anther.  Ovaries  6,  united,  each  i -celled 
and  i-ovuled;  stigmas  sessile,  plumose.  Fruit  2^  or  3  lines 
long  and  il/2  to  2  lines  thick,  oblong  or  ovate,  obtuse  at  the  base, 
with  6  recurved  points  at  the  apex.  Carpels  6,  3-angled,  flat  or 
slightly  grooved  on  the  back,  or  the  dorsal  edges  curving  upwards 
and  sharply  winged  (T.  data,  Nutt.),  separating  at  maturity  from 
a  hexagonal  axis;  seeds  much  smaller  than  the  thick  membranous 
carpels,  straight  or  slightly  curved;  raphe  not  conspicuous. 

The  distinctions  between  this  species  and  the  form  data  of 
Nuttall,  depending  upon  the  presence  or  absence  of  wings  on  the 
carpels,  are  too  inconstant  to  warrant  even  the  making  of  a  variety. 
T.  maritima  generally  occurs  on  salt  marshes,  along  the  sea- 
coast  and  on  saline  grounds  in  the  interior  of  the  country,  but  is 
not  uncommon  in  fresh  marshes,  It  is  widely  spread  on  our  con- 
tinent from  Labrador  to  New  Jersey,  and  westward  to  Alaska 
and  California.  From  Southern  Mexico  to  Terra  del  Fuego,  and 
in  Hurope  and  Asia  it  is  equally  common.  (Plate  XXII.) 


2.  SCHEUCHZERIA,  L.  Sp.  PL  338  (1753). 

Rush-like  bog  perennials  with  creeping  rootstocks  and  erect, 
leafy  stems.  Leaves  semiterete  below  and  plane  above,  striate,  fur- 
nished with  a  pore  at  the  apex  and  a  membranous,  ligulate  sheath 
at  the  base.  Flowers  small,  racemose.  Perianth  6-parted,  regu- 
lar, biserial,  persistent.  Stamens  6,  biserial,  inserted  at  the  base 
of  the  segments;  filaments  elongated;  anthers  linear,  basifixed, 
extrorse.  Ovaries  3,  rarely  4-6,  separate  or  connate  at  the  base, 
i -celled,  each  cell  containing  one  or  two  collateral  ovules.  Stig- 
mas sessile,  papillose  or  slightly  fimbriate.  Carpels  3-6,  shortly 
connate  at  base,  divergent,  inflated,  coriaceous,  1-2  seeded.  Fruit 
a  follicle,  thick,  flattish-oval,  dehiscing  laterally,  containing  one 
or  two  smooth  seeds  which  have  a  clearly  marked  raphe  and 
a  thick  hard  testa.  Seeds  exalbuminous,  straight  or  slightly 
curved,  loose  in  the  carpel. 

Only  one  species  is  known. 

i.  SCHEUCHZERIA  PALUSTRIS,  L.  Sp.  PI.  338  (1753). 

Leaves  4-16  inches  long,  the  cauline  diminishing  to  bracts 
among  the  inflorescence.  Stems  one  or  more,  rising  from  a  long 
creeping  rootstock,  and  usually  clothed  at  the  base  with  the  re- 
mains of  old  leaves,  4-10  inches  in  height;  sheaths  on  the  radical 
leaves  often  4  inches  in  length,  with  a  ligule  nearly  5  lines  long. 
Pedicels  3-10  lines  long,  spreading  in  fruit.  Flowers  white,  few,  in 
a  lax  raceme;  perianth  segments  acute  or  obtuse,  membranaceous, 
I -nerved,  \y2  lines  long,  the  inner  ones  narrower.  Stamens  2^- 
3  lines  long.  Follicles  3-4  lines  in  length,  divergent,  only  slightly, 
if  at  all  united  at  the  base.  Seeds  oval,  fuscous,  2l/2  or  3  lines  in 
length,  with  a  very  hard  testa. 

This  plant  occurs  rather  rarely  in  deep  quaking  bogs,  among 
moss  and  grass,  from  New  Brunswick  to  Hudson's  Bay  in  Canada, 
from  New  England  to  New  Jersey,  and  westward  to  Washington 
and  California.  It  is  also  an  inhabitant  of  Northern  Europe  and 
Asia.  (Plate  XXIII.  with  a  flower  magnified.) 

3.  LILyEA,  Humb.  et  Bonpl.  PI.  sEq.  i.  221  (1808). 
Annual  stemless,  paludose  plants,  with  simple,  slender  scapes 
and  radical  leaves  which  are  slightly  dilated  at  the  base.     Flowers 
monoecious  and  dimorphous,  the  one  sort  solitary,  fertile  and  dis- 


10 

posed  among  the  leaves  at  the  base,  with  long,  thread-like  styles. 
The  other  kind  of  flowers  are  monoecious,  in  dense  spikes  at  the 
apex  of  slender  scapes.  Staminate  flowers  imbricated  in  narrow, 
oblong  spikes  ;  stamen  of  a  single,  2-celled  anther  nearly  sessile,  in 
the  axis  of  a  white,  linear,  petaloid  bract  longer  than  itself.  Fertile 
flowers  imbricated  in  larger,  conical,  crowded  spikes,  bractless, 
consisting  of  a  I -celled,  i-ovuled  ovary  which  is  tipped  with  a 
capitate  stigma ;  ovules  anatropous.  Fruit  ovoid,  costate,  indehis- 
cent,  thick,  membranaceous.  Seeds  oblong-conical,  the  raphe 
filiform,  inconspicuous;  embryo  thick,  conical,  with  an  elongated 
cotyledon  and  short  radicle. 

Natives  of  western  North  America,  Mexico  and  equatorial 
South  America.  One  species  only  is  known. 

i.  LIL^EA  SUBULATA,  Humb.  et  Bonpl.  PI.  ^Eq.  i.  222,  tab.  63  (1808). 

Hctcrostylus  gra mineus,  Hook.  Fl.  Bor.  Am.  ii.  171  (1840). 

The  leaves  of  this  species  are  not,  as  described  even  by  so 
careful  an  observer  as  Micheli,  "grass-like,"  but  as  Mr.  S.  B. 
Parish,  of  San  Bernardino,  Cal.,  writes,  cylindrical,  about  the  size 
of  a  goose  quill  and  filled  with  spongy  cellulose  matter  which 
causes  them  to  become  flat  under  pressure,  and  hence  very  decep- 
tive in  herbarium  specimens.  They  are  numerous,  8  to  1 2  inches 
high,  erect,  tapering  to  a  point  at  the  apex.  Scapes  4  to  8  inches 
high,  much  shorter  than  the  leaves  and  like  them  terete.  The 
curious  basilar  flowers  produce  an  enormously  long  filiform  style, 
nearly  as  long  as  the  scapes,  sometimes  even  8  inches,  and  tipped 
with  a  capitate  stigma.  They  remind  me  very  much  of  the  similar 
flowers  and  styles  of  Scirpus  supinus  var.  Hallii  which  I  once 
found  growing  at  Winter  Pond,  Winchester,  Mass.  Their  fruit  is 
many-ribbed,  about  3  lines  in  length.  The  flowers  of  the  spikes 
are  smaller  in  size,  those  of  the  staminate  flowers  having  abortive 
fertile  flowers  mixed  with  them.  Micheli  quotes  Hieronymus  as 
saying  that  the  spikes  are  androgynous,  having  fertile  flowers  at 
the  base,  perfect  in  the  centre  and  sterile  at  the  apex,  but  none  of 
our  North  American  plants  show  this  so  far  as  I  have  seen,  nor 
does  Bonpland,  in  his  original  description,  seem  to  have  noticed 
such  an  arrangement.  Ovaries  in  the  upper  flowers  with  a  short, 
thick  style,  crowned  by  a  papillose  stigma. 


11 

In  shallow  water  or  mud.  The  plant  was  originally  collected  by 
Humboldt  and  Bonpland  near  Bogota  in  the  United  States  of 
Colombia,  but  it  has  since  been  found  in  many  other  parts  of 
South  America.  The  writer  gathered  it  at  Buenos  Aires.  It  oc- 
curs on  Vancouver's  Island  (Macoun.),  in  San  Bernardino  county, 
Cal.  (Parish),  and  Chihuahua,  Mexico  (Pringle).  (Plate  XXIV.) 

4.  POTAMOGETON,  L.     Sp.  PL  126  (1753). 

Leaves  alternate  or  the  uppermost  opposite,  often  of  two  kinds, 
submerged  and  floating,  the  submerged  linear  and  grass-like,  the 
floating  coriaceous,  lanceolate,  elliptical,  ovate  or  oval.  Spathes 
stipular,  often  ligulate,  free  or  connate  with  the  base  of  the  leaf  or 
the  petiole,  enclosing  the  young  buds  and  usually  soon  perishing 
after  expanding.  Peduncles  axillary,  usually  emersed.  Flowers 
small,  spicate,  greenish  or  rufescent.  Perianth  segments  4,  shortly 
unguiculate,  concave,  valvate  in  aestivation.  Stamens  of  4  sessile 
anthers,  inserted  on  the  claws  of  the  sepals.  Ovaries  4,  sessile, 
distinct,  i -celled,  i-ovuled,  attenuated  into  a  short,  erect  or  re- 
curved style,  or  with  a  sessile  stigma.  Fruit  of  4  ovoid  or  subglo- 
bose  drupelets,  the  pericarp  usually  thin  and  hard  or  spongy. 
Seeds  crustaceous,  exalbuminous,  campylotropous,  with  an  unci- 
nate  embryo  the  radicular  end  of  which  is  thickened.  Very  fre- 
quently amphibious  forms  of  many  of  the  floating-leaved  species 
occur,  which  it  is  difficult  to  distinguish.  These  are  dwarf,  stocky 
forms,  generally  without  submerged  leaves,  nearly  always  without 
fruit,  and  caused  by  the  drying  up  of  the  water  in  which  they 
grow.  About  the  only  method  of  deciding  the  species  in  such 
cases  is  by  the  occurrence  of  the  normal  form  in  the  adjoining 
waters,  and  by  the  coriaceous  leaves  and  stipules  which  usually 
retain  their  normal  character.  P.  pulclicr,  P.  lonc/iitcs,  P.  lietcro- 
pliyllus  and  P.  spathulafonnis  (in  England)  are  greatly  addicted 
to  this  habit. 

By  nutlet  in  the  following  descriptions  is  meant  the  crustace- 
ous seed  freed  from  the  pericarp. 

About  65  fairly  well-defined  species  occur  in  the  cool  waters  of 
the  temperate  zones  in  all  the  continents,  and  the  great  bulk  of 
them  in  northern  North  America,  Europe  and  Asia.  Of  the  37 
North  American  species,  14,  so  far  as  known,  are  confined  to  this 
country. 


12 

Stipules  axillary  and  free  from  the  leaf. 
With  floating  and  submerged  leaves. 
Submerged  leaves  bladeless. 

Nutlets  deeply  pitted.  I.  P.  n  a  tans. 

Nutlets  not  pitted.  2.  P.  Oakesianus. 

Submerged  leaves  with  a  proper  blade. 

Submerged  leaves  of  2  kinds,  lanceolate  and  oval  or  oblong. 
Uppermost  broadly  oval  or  elliptical,  lowest  lanceolate. 

3.  P.  amplifolius. 
Uppermost  lanceolate  and  pellucid,  lowest  oblong  and  opaque. 

4.  P.  pulcher. 
Submerged  leaves  all  alike,  capillary  or  linear-sectaceous. 

l-nerved  or  nerveless.  27.  P.  Vaseyi. 

3-nerved.  28.  P.  lateralis. 

Submerged  leaves  all  alike,  linear. 

Nearly  the  same  breadth  throughout,  obtusely  pointed,  coarsely  cellular-retic- 
ulated in  the  middle.  5.  P.  Nuttallii. 
Broader  at  base,  acute,  without  cellular-reticulation. 

^  IO.  P.  heterophyllus. 

Submerged  leaves  all  alike,  lanceolate. 

Fruit  strongly  embossed  or  dentate  on  the  keels.  9.  P.  Mexicanus. 

Keels  of  fruit  even. 

Uppermost  leaves  petioled,  lowest  sessile.  6.  alpinus. 

All  petioled. 

Floating  leaves  large,  broadly  elliptical,  rounded  or  subcorclate  at  base. 

12.  P.  Illinoensis. 
Floating  leaves  narrowly  elliptical,  sloping  at  base. 

7.  P.  lonchites. 
Floating  leaves  mostly  obovate  or  oblanceolate,  sloping  at  base. 

8.  P.  Faxoni. 
All  sessile  or  subsessile. 

Fruit  only  I  line  long,  obscurely  3  keeled.  II.  P.  spathulvformis. 

Fruit  \yz  lines  long,  distinctly  3-keeled.  13.  P.  angitstifolius. 

With  submerged  leaves  only. 

Without  propagating  buds  or  glands. 

Leaves  with  broad  blades,  mostly  lanceolate  or  ovate,  many  nerved. 
Leaves  subsessile  or  shortly  petioled,  mostly  acute  or  cuspidate. 

14.  P.  hicens. 
Leaves  semi-amplexicaul,  obtuse  and  cucullate  at  the  apex. 

15.  P.  prtelongus. 
Loaves  meeting  around  the  stem,  very  obtuse  at  the  apex,  not  cucullate. 

1 6.  P.  perfoliatus. 
Leaves  with  narrow  blades,  linear  or  oblong-linear,  several  nerved. 

Leaves  oblong-linear,  5-7  nerved,  obtuse  at  the  apex. 

17.  P.  Mysticus. 


13 

Leaves  narrowly  linear,  3-nerved,  acute  at  the  apex. 

23.  P,  foliosits. 

Leaves  with  narrow  blades,  capillary  or  setaceous,  i-nerved  or  nerveless. 
Peduncles  terminal,  very  long.  1 8.  P.  confervoides. 

Peduncles  axillary,  short.  19.  P.  Ctirtissii. 

With  propagating  buds  or  glands,  or  both. 
With  buds  but  without  glands. 

I /eaves  serrulate,  3— y-nerved.  20.  P.  crispus. 

Leaves  entire,  with  3  principal  and  many  fine  nerves. 

21.  P.  zosterafolius. 
Commonly  with  glands,  but  no  buds. 

Stems  long  branching  from  the  base,  leaves  lax,  plane,  3-nerved,  abruptly 
acute  or  cuspidate.  22.  P.  Hillii. 

Stems  simple,  leaves  strict,  revolute,  3-5-nervecl,  acuminate. 

26.  P.  rutilus. 
With  both  buds  and  glands. 

Glands  large  and  translucent,  buds  rare.  24.  P.  obtusifolius. 

Glands  small,  often  dull,  buds  common. 

Leaves  linear,  5~7-nerved.  25.  P.  major. 

Leaves  linear,  3-nerved.  29.  P.  pusillus. 

Leaves  capillary,  i-nerved  or  nerveless.  30.  P.  gemmiparus. 

Stipules  aclnate  to  the  leaves  or  petioles. 
With  floating  and  submerged  leaves. 

Submerged  peduncles  as  long  as  the  spikes,  clavate,  often  recurved. 

31.  P.  diversifo  Hits. 
Submerged  peduncles  none,  or  at  most  hardly  a  line  long. 

32.  P.  Spirillus. 
With  submerged  leaves  only. 

Stigma  broad  and  •sessile.  33.   P.filiforviis. 

Style  apparent,  stigma  capitate'. 

Fruit  without  keels  or  obscurely  keeled. 

Leaves  capillary,  i-nerved  or  nerveless.  34.  P.  pectinatus. 

Leaves  linear,  3~5-nerved.  35.  P.  latifolius. 

Fruit  strongly  3-keeled. 

Leaves  entire,  3~5-nerved.  36.  P.  ititerruptus. 

Leaves  minutely  serrulate,  finely  many-nerved.  37.  P.  Robbinsii. 

I.    POTAMOGETON  NATANS,  L.  Sp.  PI.   126  (l7S3). 

The  stems  of  this  species  grow  from  two  to  four  feet  in  height, 
usually  in  still  waters  with  a  muddy  bottom,  and  are  simple  or 
sparingly  branched.  Floating  leaves  thick,  coriaceous,  the  blade 
ovate,  oval  or  elliptical,  2-4  inches  long  and  1-2  inches  broad, 
usually  tipped  with  a  short,  abrupt  point,  rounded  or  sub-cordate 
at  base,  and  with  20-30  rather  strong  nerves.  The  submerged 
leaves  by  which  this  species  can  always  be  distinguished  from 
every  other  except  P.  Oakcsianus,  are  phyllodia,  without  the 


14 

slightest  sign  of  a  lamina.  I  notice  that  they  generally  form  a 
coriaceous  blade  at  their  tips  when  they  reach  the  surface,  show- 
ing that  they  are  true  petioles.  Being  attached  to  the  lower  part 
of  the  stem,  they  often  become  extremely  long.  I  have  specimens 
in  which  they  are  from  15  to  1 8  inches  in  length.  Commonly 
they  perish  early,  and  are  seldom  seen  at  the  fruiting  period. 
Stipules  long  and  acute  (sometimes  4  inches),  2-keeled.  Pedun- 
cles equalling  the  stem  in  thickness,  and  from  2  to  4  inches  in 
length.  Spikes  cylindrical,  sometimes  upwards  of  2  inches  long, 
densely  flowered  and  fruited.  Fruit  turgid,  2-2^5  lines  long 
and  about  I  ^  lines  broad,  scarcely  keeled,  narrowly  obovate, 
slightly  curved  on  the  face ;  style  short  and  facial ;  nutlet  hard, 
more  or  less  deeply  pitted  or  impressed  on  the  sides,  with  2  grooves 
on  the  back;  embryo  forming  an  incomplete  circle,  the  apex 
pointing  towards  the  base. 

The  floating  leaves  of  this  species  are  occasionally  very  obtuse 
or  acute  at  the  apex  and  sloping  at  the  base.  The  Atlantic  coast 
forms  generally  have  small  coriaceous  leaves,  while  those  of  Europe 
and  our  interior  states  are  large.  Very  rarely  floating  leaves  oc- 
cur with  as  many  as  40  nerves.  The  stipules  also  are  sometimes 
obtuse  and  usually  deciduous  beneath  the  water.  An  extreme 
form  (var.  prolixus,  Koch.),  growing  in  deep  water  and  strong  cur- 
rents, has  all  the  parts  very  slender  and  greatly  elongated.  I  have 
collected  this  with  stems  12  feet  in  length,  submerged  leaves  21 
inches  long,  and  floating  leaves  lanceolate  or  lance-oblong  and 
very  acute. 

Common  in  ponds  and  streams  throughout  Canada  and 
the  United  States,  extending  into  Mexico.  Equally  common 
in  Europe.  Occurs  also  in  Africa  and  Asia.  Fruits  in  July  and 
August  in  our  Northern  States.  (Plate  XXV.) 

2.  POTAMOGETOX  OAKESiANUS,  Robbins,  in  A.  Gray,  Man.  cd.  5. 

485  (1867). 

Stems  very  slender,  often  much  branched  from  below.  Float- 
ing leaves  elliptical,  obtuse  at  the  apex  and  rounded  or  slightly 
sub-cordate  at  the  base,  1-2  inches  long  and  5-9  lines  wide,  with 
from  12  to  20  nerves  and  slender  petioles  2-6  inches  long.  Sub- 
merged leaves  mere  capillary  phyllodia,  often  continuing  through 


15 

the  flowering  season.  Peduncles  1-3  inches  in  length,  commonly 
much  thicker  than  the  stem,  mostly  solitary.  Spikes  cylindri- 
cal, y^-i  inch  long,  usually  not  fruiting  freely.  Stipules  hardly 
keeled,  acute.  Fruit  obovate,  about  I  */£  lines  long  and  I 
line  broad,  nearly  straight  on  the  face,  3-keeled,  middle  keel 
sharp;  the  style  apical  or  often  sub-apical;  sides  of  the  nutlet  not 
pitted,  but  sometimes  slightly  impressed;  embryo  circle  incomplete, 
the  apex  pointing  towards  the  base. 

This  species  may  readily  be  distinguished  from  P.  nafans, 
which  it  resembles,  by  its  much  smaller  parts,  its  almost  uniformly 
elliptical  floating  leaves,  its  delicate  phyllodia,  thickened  peduncles, 
tricarinate  fruit,  and  even-sided  nutlet. 

My  friend,  Arthur  Bennett  (Jour.  Bot.  1890,  p.  301),  regards 
this  species  as  the  P.  Nuttallii  of  Ch.  and  Sch.  (Linnaea,  ii.  p.  226), 
which  would  give  that  name  the  priority,  having  been  published 
in  1827.  With  this  judgment  I  am  unable  to  agree,  since  it  ap- 
pears to  me  that  the  fruit  of  P.  Oakesianus  does  not  correspond  to 
the  description  or  the  figures  given  in  that  work.  It  is  there  said 
to  be  "  oblique  lenticulari-suborbicularis,"  but  in  shape  it  is 
rarely  otherwise  than  narrowly  obovate.  The  sides  of  the  nutlet 
are  said  to  be  impressed  in  the  middle,  whereas  in  this  species 
they  are  even.  Our  plant  fails  especially  to  agree  with  the  de- 
scription and  figure  of  these  authors  in  the  embryonic  curve,  their 
seed  being  said  to  be  "  cochleato-convolutum,  unico  et  paululum 
quod  supersit  anfractu,"  but  in  this  case  the  seed  is  not  cochleate- 
convolute,  nor  is  the  embryo  coiled  upon  itself,  the  apex  simply 
pointing  to  the  base.  The  figure  of  the  embryo  in  Linnaea  as 
compared  with  the  embryo  of  P.  Oakesianus  is  quite  conclusive. 
The  fruit  figured  by  Cham,  and  Schlecht.  seems  to  me  to  agree 
so  exactly  with  that  of  P.  Claytonii,  Tuck.,  that  I  have  not  hesitated 
to  adopt  their  name  for  that  species,  as  will  be  seen  below. 

The  name  here  used  was  given  by  Dr.  Robbins  in  honor  of 
his  old  and  intimate  friend,  William  Oakes,  of  Ipswich,  Mass. 

A  rather  rare  species,  occurring  in  still  waters,  Anticosti,  Canada, 
(Macoun),  N.  H.  to  N.  J.  and  westward  to  the  Adirondacks,  N.  Y. 
A  doubtful  form  is  sent  from  Nebraska  by  H.  J.  Webber.  It  is 
exceedingly  abundant  in  some  of  the  small  ponds  of  Nantucket, 
where  it  fruits  very  freely.  June-Aug.  (Plate  XXVI.) 


16 

3.  POTAMOGETON   AMPLiFOLius,   Tuckerman,  Am.  Jour.  Sci.  and 

Arts,  2d  ser.  vi.  225  (1848). 

Stems  simple,  2-5  feet  long,  occasionally  branching.  Floating 
leaves  thick,  oval  or  ovate,  abruptly  pointed  at  the  apex  and 
rounded  at  the  base,  2-4  inches  long  and  I  y±-2  inches  broad,  32-40 
nerved,  on  petioles  3  to  5  inches  in  length.  Submerged  leaves 
large,  the  uppermost  often  elliptical  or  oval,  3-6  inches  long  and 
\-2.y2  inches  broad,  having  about  the  same  number  of  nerves  as 
the  floating  and  sometimes  shining;  the  lowest  lanceolate,  acute 
at  each  end,  often  as  much  as  8  inches  long  and  2  inches  wide, 
with  about  25  nerves.  The  lowest  leaves  frequently  have  the  two 
sides  of  the  blade  closed  and  assume  a  recurved  or  falcate 
shape.  All  the  submerged  leaves  are  thin  and  pellucid,  and 
are  borne  on  short  petioles.  Stipules  tapering  to  a  long  sharp 
point,  2-keeled,  closely  embracing  the  stem  or  spreading  with  age, 
sometimes  4  inches  long.  Peduncles  thickening  upwards,  2  to  8 
inches  long.  Spikes  thick,  cylindrical,  I  to  2  inches  long.  Fruit, 
2  to  2.y2  lines  in  length  by  i^  lines  in  breadth,  with  a  thick,  hard 
shell,  turgid,  obliquely  obovate  in  shape,  3-keeled,  the  middle  keel 
prominent;  sides  not  impressed,  face  more  or  less  angled;  style, 
sub-apical;  embryo  slightly  incurved.  In  the  Western  lakes  and 
ponds  the  plants  with  the  large  oval  or  ovate  submerged  leaves 
are  most  common,  and  those  with  recurved  leaves  rare,  while  the 
reverse  is  the  case  in  Eastern  waters.  Aberrant  forms  occur  with 
petioles  very  slender  and  10  or  more  inches  in  length.  I  have 
also  collected  occasional  specimens  which  have  at  the  lowest  part 
of  the  stem  small,  opaque,  oblong,  long-petioled  leaves  similar  to 
those  found  on  P.  pulcher ;  and,  also,  a  very  rare  form  which  re- 
sembles P.  natans  in  its  upper  foliage  and  in  fruit,  except  the  em- 
bryo. Canada  from  Ontario  to  Vancouver's  Island  (Macoun). 
United  States  from  New  England  to  Kentucky,  and  westward  to 
Minnesota  and  Nebraska.  An  endemic  species.  July  to  Sept. 
(Plate  XXVII,  showing  below  one  of  the  curved  submerged 
leaves.) 

4.  POTAMOGETON  PULCHER,  Tuckerm.  Am.  Jour.  Sci.  and  Arts,  ist 

ser.  xlv.  38(1843). 

Stems  simple,  terete,  black-spotted,  from  I  to  2  feet  high. 
Floating  leaves  usually  massed  at  the  top  on  short,  lateral  branches, 


17 

alternate,  ovate  or  roundish-ovate,  sometimes  large  oval  or  nearly 
orbicular,  subcordate,  2-4^  inches  long  and  9  lines  to  31^  inches 
broad,  25-33-nerved.  Petioles  about  as  thick  as  the  stem,  2-4 
inches  long,  and  spotted  like  that.  Submerged  leaves  of  2  kinds, 
the  uppermost  pellucid,  lanceolate,  long-acuminate,  undulate,  3-8 
inches  in  length,  6-18  lines  in  width,  tapering  at  the  base  into  a 
short  petiole,  10  to  20  nerved,  irregularly  cellular-reticulated  for  a 
narrow  space  on  each  side  of  the  midrib;  the  lowest  near  the  base 
of  the  stem,  fewer,  much  thicker,  opaque,  spatulate,  oblong  or 
ovate,  with  a  rounded,  tapering  base,  on  petioles  which  are  often 
broadened  and  y2  to  4  inches  in  length.  The  submerged  leaves 
are  usually  much  decayed  at  the  time  of  flower  and  fruit,  and,  in 
order  to  get  them  in  good  condition,  they  must  be  gathered  be- 
fore the  flowering  period.  Stipules  obtuse  or  long-acuminate,  bi- 
carinate.  Peduncles  slightly  thicker  than  the  stems,  2  to  4  inches 
long.  Spikes  about  an  inch  in  length  and  densely  fruited,  when 
fruiting  at  all.  Fruit  tapering  at  top  into  a  stout  apical  style,  2 
lines  or  a  little  more  in  length  and  I  ]/2  lines  in  breadth,  thick  and 
turgid,  the  back  sharply  3-keeled,  middle  keel  prominent,  largely 
rounded  at  base;  face  angled  near  the  centre,  with  a  sinus  below; 
embryo  coiled  I  y$  times.  Aberrant  forms  with  coriaceous  sub- 
merged leaves,  and  the  floating  ones  with  slender  petioles,  10  or 
more  inches  long,  are  found  in  mill  ponds  where  the  water  has 
been  drained  off  and  the  pond  refilled.  It  occurs  sometimes,  also, 
in  very  deep  water,  when  the  upper  part  lengthens  into  slender 
simple  or  long,  branching  stems,  very  different  in  appearance  from 
the  shallow  water  forms.  It  may  also  be  found  quite  often  in 
an  amphibious  state  in  pools  which  have  become  nearly  dry,  when 
it  is  almost  without  stem  and  exhibits  coriaceous  leaves  only. 

An  endemic  species,  rare,  and  still  more  rarely  found  in  fruit. 
The  most  abundant  locality  in  which  I  have  observed  it  is  on  the 
island  of  Nantucket,  where  it  nearly  fills  some  of  the  small  ponds, 
and  fruits  quite  freely. 

Ponds,  in  Wells,  Me.  (Harvey),  Brattleboro,  Vt.  (Frost),  East- 
ern Massachusetts  to  Pennsylvania,  Georgia,  and  near  St.  Louis, 
Mo.  (Engelmann).  June,  July  (Plate  XXVIII). 


18 

5.  POTAMOGETON  NuxTALLii,  Ch.  and  Sch.  Linnaea,  ii.  226,  t.  vi.  f. 

25  (1827). 

P.  Pennsylvania^,  Ch.  and  Sch.  Linn.  ii.  227  (1827). 
P.  pnmilns,  Wolfg.  in  R.  and  S.  Mant.  iii.   354  (1827),  fide.  Ar. 

Benn.  Jour.  Bot.  xxix.  307. 
P.  Claytonii,  Tuckerm.  Am.  Jour.  Sci.  and  Arts,  ist,  ser.  xlv.  38 

(1843)- 

Stems  slender,  compressed,  mostly  simple,  generally  from  i  to 
3  feet  high,  but  sometimes  6  feet  according  to  the  depth  of  the 
water  in  which  it  grows.  Floating  leaves  elliptical,  sometimes 
obovate,  obtuse  at  the  apex,  sloping  at  the  base  into  a  short 
petiole,  I  ^£-3^2  inches  long  and  4-1 2  lines  wide,  12-27  nerved. 
These  leaves  sometimes  number  as  many  as  4  or  5  pairs  at  several 
inches  distance  from  each  other  on  the  upper  part  of  the  stem. 
Submerged  leaves  linear,  2-ranked,  2-7  inches  in  length  and  1-3 
lines  in  width,  5 -nerved,  the  2  outer  lateral  nerves  nearly  marg- 
inal, the  space  between  the  two  inner  and  the  midrib  evenly  and 
coarsely  cellular  reticulated.  In  young  plants  the  submerged  leaves 
are  often  crowded  close  together,  the  internodes  afterwards  elon- 
gating. Stipules  obtuse,  hyaline,  nerved,  keelless.  Peduncles 
about  ,the  thickness  of  the  stem,  1-5  inches  long.  Spikes  ^-i 
inch  long,  fruiting  freely.  Fruit  roundish-obovate,  1^-1%  lines 
long  by  i-i^  lines  broad,  3-keeled,  middle  keel  sharp,  the  sides 
flat  and  distinctly  impressed;  style  short,  apical.  Embryo  coiled 
i^  times. 

Abnormal  forms  occur  with  stems  bearing  many  short  lateral 
branches,  and  with  branched  peduncles. 

As  has  been  stated  under  No.  2,  I  regard  this  species  as  con- 
forming so  closely  to  the  figures  and  description  of  the  fruit  of  P. 
Nuttallii,  as  given  by  Cham,  and  Sch.,  that  I  cannot  question  their 
identity.  Otherwise  I  should  have  adopted  their  name  P.  Pennsyl- 
vanicus,  given  a  little  later  in  Linnaea,  of  which  only  the  foliage  is 
described.  The  truth  seems  to  be  that  only  fruit  was  seen  in  the 
one  case  and  only  foliage  in  the  other,  and  these  authors  described 
them  under  different  names. 

So  far  as  known,  this  species  is  peculiar  to  this  country. 

Common  in  ponds  and  streams  throughout  Canada,  and  froirT 
New  England  to  Pennsylvania  and  South  Carolina,  and  westward 


19 

to  Oregon.      (Plate  XXIX.,  showing  submerged  leaves  on  the 

right.) 

6.  POTAMOGETOX  ALPiNus,  Balbis,  Misc.  Bot.  p.  13  (1804). 

P.  mfcscens,  Schrad.  ap.  Cham.  Ad.  Fl.  Ber.  p.  5  (1815). 

As  an  illustration  of  the  confusing  extent  to  which  synonymy 
has  been  carried  in  this  family  of  plants,  Mr.  Bennett  enumerates 
(Jour.  Bot.  xxvii.,  242)  21  names  given  to  this. species  by  differ- 
ent authors. 

Entire  plant  of  a  ruddy  tinge,  especially  the  leaves  and 
spikes.  This  is  very  apparent  in  clear  water.  Stems  simple  or 
sparsely  branched,  somewhat  compressed;  internodes  usually  very 
long.  Floating  leaves  coriaceous,  spatulate  or  oblanceolate,  obtuse, 
sloping  into  petioles  1-5  inches  long,  17-21  nerved,  mostly  oppo- 
site, the  midrib  with  a  chain-like  areolation  on  each  side.  Sub- 
merged leaves  thin,  semi-pellucid,  the  lowest  sessile,  the  upper- 
most petioled,  opposite  under  the  branches  and  peduncles,  oblong- 
linear  or  linear-lanceolate,  obtuse  or  rarely  acute,  narrowing  at 
base,  3-12  inches  long  and  2-9  lines  wide,  7-17  nerved.  Stipules 
broad,  faintly  bicarinate,  with  many  fine  nerves,  pellucid  on  the 
edges,  obtuse  or  very  rarely  acute.  Peduncles  about  the  thickness 
of  the  stem,  2-8  lines  long,  sometimes  3  or  4  or  even  more  near  the 
summit  of  the  stem.  Spikes  cylindrical,  i-il/2  inches  in  length, 
densely  fruited,  occasionally  appearing  compound.  Fruit  obovate, 
lenticular,  smooth,  reddish  in  color,  about  I  ^  lines  long  by  I  line 
wide,  3-keeled,  middle  keel  sharp,  almost  winged,  sloping  on  each 
side  into  obscure  lateral  keels;  face  arched  and  beaked  by  a  short 
recurved  style;  apex  of  the  embryo  pointing  directly  to  the  basal 
end.  It  is  stated  by  Dr.  Robbins  in  Gray's  Man.  Ed.  5,  that  the 
fruit  is  "pitted  when  immature."  In  mature  fruit  no  pit  is  seen. 
The  nutlet  shows  smooth  even  sides,  with  a  shallow  depression 
near  the  base  of  the  facial  edge,  and  two  obscure  furrows  on  the 
back.  This  species,  though  common  in  Europe,  while  widely  dif- 
fused is  rare  in  our  country. 

Greenland;  Canada  from  Nova  Scotia  to  Vancouver's  Island 
(Macoun);  near  Fort  Yukon,  Alaska  (Kennicot);  St.  John's  River, 
Maine  (Pringle);  Barnet,  Vt.  (Dr.  Blanchard);  Brattleboro,  Vt. 
(Frost);  Lake  Champlain,  on  the  Vermont  and  New  York  sides 
(Faxon,  Morong);  State  line,  Western  Massachusetts  (Robbins); 


20 

Niagara  Falls,  N.  Y.  (Morong);  Delaware  River,  Belvidere,   N.  J. 

(Britton);  Beaver  River,  Mich.  (Hill);  Vermilion  Lake,  Minn.  (L.  H. 

Bailey);  National  Park  (Clifford  Richardson);  Utah  (M.  E.  Jones); 

Oregon  (Howell).     Attributed  by  Brewer  and  Watson  in  Bot.  Cal. 

to   Montana,   Colorado   and    California.      July,  August.      (Plate 

XXX.) 

7.  POTAMOGETON  LONCHiTES,  Tuckerm.  Am.  Jour.  Sci.  and  Arts, 

2d  ser.  vi.  226  (1848). 
P.  fluitans.  Tuckerm.  Am.  Jour.  Sci.  and  Arts,  2d  ser.   vii.   348 

(1849),  not  Roth? 

P.  fluitans,  Roth,  Fl.  Germ.  i.  p.  72  (1788)? 
P.  Amcricanus,  Ch.  and  Sch.  Linnaea,  ii.  226,  t.  vi.  f.  25  (1827)? 

Stem  slender,  terete,  much  branched,  elongated,  3  to  6  feet 
and  sometimes  more  in  length.  Floating  leaves  coriaceous,  usu- 
ually  rather  thin,  elliptical,  pointed  at  both  ends,  2  to  4  inches 
long  and  6  to  14  lines  wide,  17  to  24  nerved,  on  petioles  2  to  8 
inches  in  length.  Submerged  leaves  very  thin  and  pellucid,  often 
with  an  irregular  cellular-reticulated  space  on  each  side  of  the 
midrib,  4  to  13  inches  long  by  2  to  12  lines  wide,  rather  rounded 
at  base  or  tapering  gradually  into  a  petiole  I  to  4  inches  long. 
The  stipules  vary  much  in  different  plants,  usually  3  or  4  inches 
long,  but  often  only  I  or  2  inches  long,  acuminate,  acute  or  ob- 
tuse, strongly  or  faintly  bicarinate.  Peduncles  thickening  up- 
wards, 2  to  3  inches  long.  Spikes  cylindrical,  I  to  2  inches  long, 
densely  fruited.  Fruit  I  ^  to  2  lines  long,  by  I  to  I  ^  lines  wide, 
obliquely  obovate,  face  nearly  straight  or  rarely  slightly  angled  or 
rounded,  back  3-keeled,  middle  keel  prominent,  strongly  rounded 
or  often  with  a  projecting  wing  just  under  the  curve  of  the  style, 
not  impressed  on  the  sides;  style  short,  facial;  embryo  slightly  in- 
curved, the  apex  pointing  slightly  inside  of  the  base. 
Var.  NOWEBORACENSIS,  n.  var. 

With  larger  and  thicker  floating  leaves,  the  blades  3  to  5*/£ 
inches  long  by  i  ^  inches  wide,  20  to  24  nerved,  abruptly  pointed 
or  rarely  obtuse  at  the  apex  and  rounded  or  sloping  at  the  base. 
Peduncles  sometimes  4  or  5  inches  long  and  the  spikes  3  inches. 
The  submerged  leaves  and  fruit  like  those  of  the  type.  This  form 
occurs  in  Lake  Erie,  Lake  Cayuga,  Niagara  river,  Oneida  Lake, 
Lake  Seneca,  the  Erie  Canal  near  it,  and  in  stagnant  pools  empty- 


21 

ing  into  the  same  lake,  New  York.  It  is  the  plant  described  by 
Tuckerman  in  Am.  Jour.  Sci.  and  Arts,  1.  c.,  under  the  name  of 
"P.fluitans,  Roth." 

I  have  hesitated  much  in  regard  to  the  naming  of  this  species, 
but  in  the  present  confused  state  of  opinion  concerning  the  status 
of  P.fluitans,  Roth,  I  can  see  no  other  method  of  disposing  of  it 
except  to  retain  Tuckerman's  name  lonchites  as  the  type  and  to 
regard  the  New  York  form  as  a  variety.  I  have  a  large  set  of  the 
English  plants  from  Mr.  Fryer,  named  by  him  "P.  fluitans,  Roth," 
and  our  typical  form  agrees  very  well  with  these,  but  as  Mr.  Fryer 
states  that  the  English  plant  is  never  known  to  fruit,  and  he  has 
reason  to  regard  it  as  a  hybrid,  we  cannot  accept  it  as  our  lon- 
chites, for  that  is  most  certainly  not  a  hybrid,  as  it  fruits  abundantly 
and  occurs  in  widely  separated  localities,  and  often  where  neither 
of  the  supposed  parents  are  found.  I  have  also  numerous  speci- 
mens of  the  continental  plant  called  by  many  authors  P.flmtaiis, 
Roth.  Our  variety  Nav&boracensis  corresponds  very  closely  to 
specimens  sent  me  by  Dr.  Tiselius,  collected  in  the  river  Neckar, 
the  fruit  being  almost  identical  with  that  of  our  species,  and  if  I 
could  be  sure  that  his  plant  is  the  true  fluitans,  my  hesitation 
would  be  at  an  end,  but  that  is  in  dispute.  The  late  Prof.  Caspary 
favored  me  with  beautiful  specimens  collected  in  Russia,  identical 
with  those  of  Dr.  Tiselius,  and  labelled  "P.  fluitans,  Roth,"  show- 
ing the  opinion  of  this  celebrated  botanist.  To  throw  doubt  upon 
the  determination,  however,  there  come  from  France  plants  bear- 
ing the  same  kind  of  foliage  as  these,  but  with  a  totally  dissimilar 
fruit,  and  still  called  "P.fluitans,  Roth."  Considering  the  fact  that 
Roth  only  describes  the  foliage  of  his  plant,  apparently  never  hav- 
ing seen  the  fruit,  that  no  authentic  species  of  his  naming  has 
ever  been  discovered,  and  that  various  European  authors  differ  so 
widely,  there  is  no  other  course  left  but  the  one  here  adopted. 
Of  one  thing  I  am  certain,  the  plants  from  Dr.  Tiselius  and  Prof. 
Caspary  are  our  New  York  species,  and  that  is  but  a  larger  form 
of  our  loncJdtes.  I  have  little  doubt,  also,  that  the  species  the  fruit 
of  which  is  figured  and  described  by  Cham,  and  Schlecht.  under 
the  name  of  P.  Anicricanus  is  our  plant. 

Widely  diffused  in  this  country.  New  Brunswick  and  Ontario 
(Macoun).  New  England  to  Florida  and  Texas  and  westward  to 


22 

Washington  and  California.      Also  Mexico  and  Cuba.     July-Oc- 
tober.    (Plate  XXXI.,  showing  a  submerged  leaf  on  the  right.) 

8.  POTAMOGETON  pAXONi,  Morong.  n.  sp. 

A  plant  collected  by  Mr.  Edwin  Faxon  in  the  years  1880  and 
1882  in  Lake  Champlain  at  Ferrisburg,  Vt.,  which  has  been  re- 
ferred to  P.  rufcscens,  but  is  evidently  quite  a  different  species.  Mr. 
Arthur  Bennett,  to  whom  I  sent  specimens,  suggests  in  Jour.  Bot. 
xxviii,  301,  that  it  may  be  a  hybrid  between  P.  rufesccns  and  P. 
Nuttallii  (Claytonii),  and  also  states  that  it  greatly  resembles  his  P. 
Griffitlni,  but  cannot  with  certainty  be  classed  under  that  species. 
If  it  is  to  be  regarded  as  a  hybrid,  which  may  be  the  case,  I  should 
much  rather  consider  it  the  offspring  of  P.  lonchites  and  P. 
rufesccns,  as  both  of  those  species  abound  in  the  vicinity,  and  on 
the  whole  it  more  nearly  resembles  the  former  than  any  other 
North  American  species. 

Floating  leaves  numerous,  thick,  coriaceous,  mostly  obovate  or 
oblanceolate,  bluntly  pointed  or  obtuse  at  the  apex  and  sloping 
into  the  petiole  at  base,  many  of  them  obovate  like  those  of  mfcs- 
cens,  and  often  strikingly  like  those  of  spatlnil<zformis,  2-$l/2 
inches  long  and  8-12  lines  wide,  13-17  nerved,  on  petioles  2  to  6 
inches  in  length.  Submerged  leaves  oblong-lanceolate,  acute  or 
sometimes  obtuse,  3-5  inches  long  and  6-12  lines  wide,  5-13 
nerved,  often  with  an  irregular  areolation  on  each  side  of  the 
midrib ;  on  petioles  J/j-2  inches  in  length.  The  nerves  run  into 
the  apices  of  the  leaves,  and  the  numerous  cross  veins  slope 
slightly  upward  at  a  large  angle  from  the  midrib.  Peduncles  a 
little  thicker  than  the  stem,  2  to  5  inches  long.  Spikes  I  to  2 
inches  long,  densely  flowered.  No  fruit  found. 

The  plant  occurs  in  the  still  waters  of  the  lake  and  also  in  the 
rapids  of  creeks  emptying  into  the  lake. 

It  is  named  in  honor  of  Mr.  Edwin  Faxon,  of  Jamaica  Plain, 
Mass.,  who  was  the  first  to  collect  it.  (Plate  XXXII). 

9.  POTAMOGETON  MEXICANUS,  Ar.  Bennett,  Jour.   Bot.  xxv.   289 
(1887). 

I  have  seen  only  the  fruit  of  this  species.  The  following  is  Mr. 
Bennett's  description  of  the  stem  and  foliage:  "  Rootstock  creep- 
ing; stems  simple.  Lower  leaves  3-5  inches  long,  alternate  strap- 
shaped,  elliptical,  tapering  at  either  end;  petioles  3-5  inches  long. 


23 

Upper  leaves  3-4  inches  long,  alternate  (or  occasionally  opposite), 
elliptical,  coriaceous,  with  14-16  principal  ribs,  and  occasionally 
secondary  ones  which  fall  short  of  the  apex  and  anastomose  with 
the  cross-veins;  areolation  distinct  over  the  whole  leaf;  petioles 
2-6  inches  long.  Peduncles  2  inches  long,  slightly  thickening  up- 
wards. Fruiting  spikes  i-i^  inches  long,  rather  few  flowered." 

The  fruit  of  this  species  is  very  distinct.  Drupe  2  lines  long, 
I  y2  lines  wide,  strongly  tricarinate,  the  middle  keel  prominent, 
sharp  and  denticulate,  while  the  lateral  keels  are  strikingly  em- 
bossed with  protuberances;  face  slightly  curved;  style  stout,  short, 
facial. 

Named  and  described  from  specimens  in  the  Herbarium  of  the 
British  Museum  collected  by  Schmitz  in  the  valley  of  Myrica, 
Mexico,  and  at  Berlin  collected  by  Schaffner,  Aug.,  1854,  in  a 
river  near  Chasseltepec,  Mexico.  (Plate  XXXIII.  The  figure  of 
the  plant  is  from  a  drawing  of  Mr.  Bennett.) 

IO.    POTAMOGETON    HETEROPHYLLUS,  Schreb.  Spicileg.    Fl.    Lips.  21 

(1771). 

P.  gramincus,  Kries,  Nov.  Ed.  2,  p.  36  (1828),  not  L. 

P.  gramincHs,  var.  hetcrophyllus,  Fries,  Nov.  Ed.  2,  p.  35  (1828). 

A  very  variable  species.  Stems  slender,  compressed,  much- 
branched,  from  i  to  2  feet  high,  usually  growing  in  quiet  water. 
Floating  leaves  coriaceous,  oval  or  elliptical,  short-pointed  at  the 
apex  and  rounded  or  sloping  at  the  base,  occasionally  sub-cordate, 
8  lines  to  \y2  inches  long  and  4-6  lines  wide,  with  10-18  nerves; 
petioles  1-4  inches  in  length.  Submerged  leaves  pellucid,  sessile, 
lanceolate  or  linear-lanceolate,  acuminate  or  cuspidate,  those  of 
the  type  rather  stiff,  1-3  inches  long  and  1-6  lines  wide,  with  3-7 
nerves,  the  uppermost  often  petiolate.  Peduncles  often  thickened 
upwards,  1-4,  rarely  7,  inches  in  length,  often  clustered  at  the  top 
of  the  stem.  Stipules  loose,  spreading,  obtuse,  2-keeled,  8-12 
lines  long.  Spike  ^-i}/£  inches  long,  usually  fruiting  freely. 
Fruit  roundish  or  obliquely  obovate,  ^-il/2  lines  long  by  ^-i 
line  broad,  slightly  curved  or  angled  on  the  ventral  side,  rounded 
and  indistinctly  3-keeled  on  the  back,  the  obovate  forms  with  an 
inward  basal  curve  on  the  face  and  an  indentation  running  into  it 
from  the  centre  of  the  sides;  style  short,  obtuse,  apical,  rarely 


24 

facial;    apex  of  the  embryo  nearly  touching  the  base,  pointing 
slightly  inside  of  it. 

The  many  forms  of  this  species  may  be  named  as  follows : 

Forma  GRAMINIFOLIUS  (Fries),  Morong. 
var.  graminifolius,  Fries.  Novit.  36  (1828). 

This  varies  from  the  type  in  having  delicate,  flaccid,  linear  sub- 
merged leaves  from  2  to  5  inches  long  and  1-3  lines  wide.  It  is 
often  found  with  the  type  and  gradually  runs  into  it. 

Forma  LOXGIPEDUNCULATUS  (Merat),  Morong. 
P.  longipcdunculatus,  Merat,  Fl.  Paris. 

This  I  had  named  forma  elongatns  until  informed  by  Mr.  Ben- 
nett that  it  occurs  in  the  work  of  Merat  under  the  present  name. 
It  has  submerged  leaves  1-2  inches  long  and  2-3  lines  wide, 
sharp-pointed,  the  internodes  naked  and  extremely  long,  fre- 
quently as  much  as  10  inches.  Peduncles  3-6  inches  long. 
Floating  leaves  ovate. 

I  collected  this  in  deep  water  in  Lake  Erie,  near  Buffalo,  and 
Lake  Seneca,  N.  Y.  Prof.  L.  H.  Bailey  has  since  obtained  it  in 
Vermilion  Lake,  Minn.,  and  Mr.  F.  V.  Coville  in  Chenango  River, 
N.  Y. 

Forma  MYRIOPHYLLUS  (Robbins),  Morong. 
Var.  ?  mynophyllus,  Robbins,  in  A.  Gray,  Man.  Ed.  5,  p.  487  (1867). 

An  interesting  form  with  long  running  rootstocks  which  send 
up  dichotomously  branching  and  very  leafy  stems.  Submerged 
leaves  delicate,  about  I  inch  long  by  2  lines  wide,  3-5  nerved, 
linear  or  the  upper  ones  oblanceolate.  Floating  leaves  elliptical 
or  lance-oblong.  This  form  often  throws  up  very  long,  naked, 
thread  like  stems,  which  bear  long-petioled  floating  leaves,  while 
the  submerged  leaves  are  on  short  lateral  branches  near  the  base. 
These  and  the  "early  perishing  submerged  stem  leaves"  of  which 
Robbins  speaks  are  found  only  in  a  mill  pond  at  Apponaug,  R.  L, 
the  locality  in  which  the  form  was  first  discovered,  and  are  caused 
by  the  frequent  variation  in  the  depth  of  the  water,  now  drained 
off  and  now  suffered  to  rise.  When  the  pond  is  low,  the  plants 
spring  up  and  bear  floating  coriaceous  leaves  which  are  suddenly 
submerged  by  a  rise  in  the  water  and  very  soon  perish.  The 
plant  in  order  to  meet  the  new  conditions  throws  up  proliferous 
stems  which  produce  a  new  set  of  floating  leaves. 


25 

This  form  is  also  remarkable  for  its  tuberous  rootstocks,  which 
are  very  abundant. 

I  have  collected  this  not  only  in  Apponaug  pond,  but  also  in 
Waushakum  pond,  Ashland,  Mass.,  and  Lake  Quinsigamond, 
Worcester,  Mass.  It  occurs  also  in  Lake  Saltonstall,  near  New 
Haven,  Conn.  (Prof.  O.  D.  Allen.) 

Forma  MINIMUS,  Morong. 

A  very  rare  form,  with  long,  almost  capillary  stems  and  inter- 
nodes  3  to  4  inches  in  length.  Submerged  leaves  thickly  clus- 
tered on  short,  lateral  branches,  ^  to  I  inch  long  and  scarcely  ^  line 
wide,  acuminate,  I -nerved,  some  of  them  with  the  nerve  obscured. 
Floating  leaves  ^  to  I  ]/2  inches  long  and  3  to  9  lines  wide,  lance- 
olate, oval  or  ovate,  usually  clustered  at  the  summit  of  the  stem. 

This  form  I  collected  in  Spot  Pond,  Stoneham,  Mass.,  and  it  has 
also  been   detected    in   Lake  Winnepesaukee,  N.  H.,  by  W.  F. 
Flint.     The  minute  submerged  leaves,  clustered  on  short,  lateral 
branches  are  quite  striking. 
Forma  MAXIMUS  Morong. 
Var.  inaxiinns,  Morong,  without  description,  Bull.  Torr.  Bot.  Club, 

xiii.  155. 

All  the  parts  greatly  elongated.  Stems  sometimes  10  to  12 
feet  in  length.  Floating  leaves  often  lanceolate  and  sharply 
pointed,  3  to  4  inches  long  and  6  to  14  lines  wide.  Submerged 
leaves  2  to  6^  inches  long  and  3  to  8  lines  wide,  5  to  9  nerved. 
Specimens  collected  by  Prof.  O.  D.  Allen,  in  Lake  Whitney, 
Conn.,  have  large,  oval,  floating  leaves  with  from  29  to  31  nerves, 
and  submerged  leaves  with  1 3  nerves.  Peduncles  2  to  4  inches 
long,  usually  much  thickened  upwards,  often  at  right  angles  to  the 
stem,  a  peculiarity  which  I  have  observed  in  specimens  from  other 
localities  also.  This  form  greatly  resembles  one  sent  by  Dr. 
Tiselius  from  Sweden,  and  named  by  him  var.  fluctuans.  It  com- 
monly occurs  in  swiftly  flowing  water,  to  which  fact  the  elonga- 
tion of  the  parts  is  doubtless  largely  owing. 

Charles  river,  Mass.,  Saranac  river,  Adirondacks,  N.  Y.,  and 
Connecticut  river,  Deerfield,  Mass.  (Morong);  Lake  Vermilion, 
Minn.  (L.  H.  Bailey);  Pine  Plains,  N.  Y.  (Hoysradt);  Delaware 
river,  N.  J.  (Porter);  flowing  water,  Busic  river,  Anticosti  (Ma- 
coun). 


Besides  the  localities  of  peculiar  forms  mentioned  above,  the 
range  of  the  species  is  indicated  by  the  following  stations.  Com- 
mon throughout  Canada  from  the  Atlantic  to  the  Pacific  and 
from  Maine  and  Vermont  through  New  Jersey  to  North  Carolina ; 
Lake  Huron  (Macoun.);  Sault  Ste.  Marie,  Mich.  (Morong);  Chicago, 
111.  (Babcock);  Armstrong's  Grove,  Iowa  (Cratty);  Sherburne  Geyser 
Basin,  National  Park  (Clifford  Richardson);  Falcon  Valley,  Wash- 
ington (Suksdorf);  Salt  Lake  City,  Utah  (M.  E.  Jones);  Ruby 
Lake,  Nevada  (Watson).  Attributed  by  Brewer  and  Watson, 
Bot.  Cal.,  to  Soda  Spring,  near  Mono  Pass,  Cal.  (Plate  XXXIV., 
submerged  leaves  on  the  left.) 

ii.  POTAMOGETON  spATHUL/EFORMis  (Robbins)  Morong. 
P.  gramineus,  var.  ^spatliulcefonnis,  Robbins  in  A.  Gray,  Man.  Ed. 

5,  p.  487(1867). 

P.  spathceformis,  Tuck,  in  Herb. 
P.  varians,  Morong  in  Herb. 

Rootstock  running,  producing  many  branching  stems  2-3  feet 
high.  Floating  leaves  obovate,  sometimes  elliptical,  abruptly 
acute  at  the  apex  and  usually  sloping  at  base,  rather  thin,  13-23 
nerved,  1-2*^  inches  long  and  6-13  lines  wide,  on  slender  petioles 
1-4  inches  in  length.  Submerged  leaves  pellucid,  spatulate-oblong 
or  linear-lanceolate,  2-4  inches  long  and  3-9  lines  wide,  5-13 
nerved,  cuspidate  or  spinescent  at  the  apex  and  sloping  at  base, 
all  sessile  at  first,  with  age  subsessile  or  even  petioled.  The  sub- 
merged leaves  are  often  reduced  to  phyllodia  or  forms  with  a  very 
narrow  blade  and  a  long  acumination  at  the  apex  and  base.  Pe- 
duncles often  thickening  upwards,  1-2  inches  long.  Stipules  ob- 
tuse, faintly  keeled,  the  apex  slightly  cucullate  and  splitting  on 
pressure.  Spikes  large,  densely  flowered.  Fruit  like  that  of 
hcterophyllus,  about  I  line  long  by  ^  line  broad,  roundish  or 
obliquely  obovate,  obscurely  3-keeled,  with  a  curved  or  slightly 
angled  face  ;  style  apical  or  facial ;  embryo  with  the  apex  nearly 
touching  the  base  and  pointing  slightly  inside  of  it. 

This  plant  was  discovered  by  Prof.  E.  Tuckerman  as  long  ago 
as  1850  in  Mystic  Pond,  Medford,  Mass.,  and  named  P.  spathczforinis 
in  his  herbarium.  Dr.  Robbins  obtained  it  afterwards  from  the  same 
locality  in  1856  and  1867,  and  published  it  as  above  cited.  The 
present  writer  visited  the  spot  several  times  in  1879-81  and  found 


27 

it  growing  vigorously.  No  other  locality  for  it  is  known  in  this 
country.  It  is,  however,  common  in  Cambridgeshire,  England, 
and  Mr.  Fryer  has  kindly  sent  me  a  fine  suite  of  specimens  col- 
lected in  that  locality.  Here  it  has  never  been  observed  in  fruit, 
but  it  fruits,  though  not  very  freely,  in  England.  The  fruit,  which 
is  characterized  from  British  specimens,  shows  a  near  alliance  to 
P.  licteropliyllus,  from  which,  however,  it  differs  considerably  in 
other  points.  Indeed,  while  it  resembles  heterophyllus  on  the  one 
side,  it  exhibits  a  decided  likeness  to  P.  angustifolius  on  the  other, 
and  accordingly  it  has  sometimes  been  ranked  with  the  one  species 
and  sometimes  with  the  other.  Mr.  Fryer,  whose  opinion  in  any 
matter  relating  to  the  Potamogetons  of  his  district  deserves  great 
weight,  is  inclined  to  regard  this  species  as  a  hybrid  between 
keteropkyllus  and  angustifolius,  and  there  are  strong  reasons  for 
suspecting  that  it  may  be  a  hybrid,  such  as  the  fact  that  the 
anthers  are  usually  either  destitute  of  pollen,  or  possess  only  un- 
potential  pollen,  and  hence  their  inability  to  fertilize  the  stigmas, 
and  the  limited  area  of  its  growth.  But  a  weighty  argument 
against  this  view  is  the  fact  that  neither  of  the  supposed  parents 
occurs  in  Mystic  Pond,  and  that  it  should  be  produced  in  localities 
separated  by  the  Atlantic  ocean. 

July-August.  (Plate  XXXV.  The  fruit  is  figured  from  British 
specimens  supplied  by  Mr.  Fryer.) 

1 2.  POTAMOGETON  iLLixoENSis,  Morong,  Bot.  Gaz.  v.  50  (1880.) 

Stem  from  a  thick  running  rootstock,  stout,  much-branched 
above.  Floating  leaves  opposite,  numerous,  thick,  coriaceous, 
4/4-5/6  inches  long,  2-3^  inches  wide,  the  apex  with  a  short, 
blunt  point,  rounded  or  sub-cordate  or  sometimes  sloping  at  base, 
oval  or  broadly  elliptical,  i8-2/-nerved.  Petioles  often  broad  and 
flattened,  3-4  inches  long.  Submerged  leaves  numerous,  usually 
lanceolate,  4-8  inches  long  and  I -2  inches  wide,  13-19-nerved, 
acuminate  or  the  uppermost  acute  like  the  floating,  occasionally 
sessile,  but  for  the  most  part  sloping  at  the  base  into  a  short, 
broad,  flat  petiole.  These  leaves  are  of  a  very  dark  green  color, 
with  a  conspicuous  midrib,  rarely  reduced  to  phyllodia  or  to  leaves 
with  a  long,  phyllodia-like  apex  and  base,  expanding  into  a  narrow 
blade  in  the  middle. 


28 

Stipules  2-3  inches  long,  obtuse,  strongly  bicarinate.  Peduncles 
usually  thicker  than  the  stem,  sometimes  thickening  upwards,  2-4 
inches  in  length.  Spikes  1-2  inches  long,  fruiting  freely.  Fruit 
roundish  or  obovate,  il/2-2  lines  long  and  i-il/2  lines  broad,  dor- 
sally  3-keeled,  the  middle  keel  sharp ;  straight  or  curved  on  the 
face ;  style  facial,  short,  bluntish  ;  apex  of  the  embryo  pointing 
transversely  inwards. 

This  species  is  evidently  allied  to  Ittcens  in  habit,  and  with  that 
species,  P.  angustifolius,  P.  spathul&forinis  and  P.  hcterophyllns, 
forms  a  very  natural  group,  but  it  is  clearly  distinct  from  all  of 
them  in  its  vigorous  growth,  its  abundant  foliage,  its  ample  float- 
ing and  submerged  leaves,  and  its  large,  strongly  3-keeled  fruit. 

In  two  or  three  recent  publications  some  doubts  have  been 
thrown  upon  the  specific  status  of  this  plant,  which,  considering 
its  mirked  individuality,  are,  to  say  the  least,  rather  surprising. 
Mr.  Hill,  in  Bull.  Chicago  Ac.  for  1891,  p.  125,  says:  "*  *  * 
a  doubtful  species  at  best."  It  seems  to  me  not  half  so  doubtful 
as  many  other  species  of  good  standing  that  might  be  mentioned. 
In  fact,  its  peculiarities  are  strikingly  manifest. 

In  A.  Gray,  Man.  Ed.  6,  it  is  said  to  be  "  very  near  amplifolius" 
a  species  with  which  it  has  very  few  characters  in  common.  The 
eminent  Scandinavian  Potamogetonist,  Dr.  Tiselius,  whose  au- 
thority upon  Northern  European  species  no  one  will  question, 
identifies  it  with  P.  lonchites  (sub.  nom.  P.  fluitans,  Roth.*),  but  it 
certainly  bears  little  resemblance  to  any  form  of  that  species  grow- 
ing in  this  country.  Nor  does  it  square  with  any  of  the  examples 
of  this  species  sent  to  me  from  Sweden  by  my  distinguished 
friend.  In  his  article  he  compares  the  floating  leaves  of  my  species 
with  those  of  autumnal  shoots  of  P.  fluitans,  and,  finding  them 
similar,  rather  hastily,  I  think,  pronounces  them  specifically  identi- 
cal, but  he  overlooks  the  fact  that  non-fruiting  autumnal  growths 
are  nearly  always  abnormal.  Were  there  no  other  differences,  the 
entire  dissimilarity  between  these  two  species  in  the  stipules,  sub- 
merged foliage  and  fruit  are  quite  sufficient  to  separate  them 
widely. 

Our  plant  was  first  discovered  by  Mr.  H.  N.  Patterson   in  the 

*See  Nordstedt's  Botaniska  Xotiser  for  1887,  p.  263. 


29 

Mississippi  river  bottoms  at  Oquawka,  111.,  and  sent  by  him  to 
Prof.  E.  Tuckerman,  who  in  turn  transmitted  it  to  Dr.  Robbins,  by 
whom  it  was  considered  as  an  extraordinary  floating-leaved  form  of 
P.  luccns.  It  has  since  been  found  by  Mr.  R.  I.  Cratty  in  a  small 
pond  at  Armstrong's  Grove,  Emmet  county,  Iowa.  Both  of  these 
gentlemen  have  supplied  me  with  numerous  specimens  in  all  stages 
of  growth,  from  which  it  has  been  easy  to  deduce  the  characters. 
I  have  not  seen  it  from  any  other  locality,  though  it  should  be  ex- 
pected in  all  the  neighboring  regions.  Fruits  in  August.  (Plate 
XXXVI.) 
13.  POTAMOGETON  ANGUSTiFOLius,  Berch.  and  Presl,  Rost.  p.  19 

(1821),  fide  A.  Bennett. 
P.  Zizii,  Roth,  En.  PI.  Germ.  {.531  (1827).  ' 
/'.  hctcrophyllus  elongates,  M.  and  K.  Deut.  Fl.  i.  845  (1823). 
P.  luccns,  var.  heterophyllus,  Fries,  Nov.  Ed.  2,  34  (1828). 
P.  luccns  var.  minor,  Nolte  in  Hans.  Ex.  No.  521,  British  Mus., 

fide  A.  Bennett. 

Stem  slender,  branching.  The  branches  rise  from  the  stem  at 
an  acute  angle,  occasionally  at  a  right  angle.  Floating  leaves 
coriaceous  or  semi-coriaceous,  rarely  shining  on  the  upper  surface, 
elliptical,  pointed  or  abruptly  acute  at  the  apex,  sloping  at  base, 
the  blade  \y2  to  4  inches  long  and  6  to  12  lines  wide,  with  13  to 
21  nerves;  petioles  commonly  shorter  than  the  blade,  but  some- 
times attaining  a  length  of  6  inches.  Submerged  leaves  mostly 
lanceolate  or  oblanceolate,  occasionally  oblong-spatulate,  thin,  pel- 
lucid, acute  or  cuspidate,  sometimes  acuminate,  often  wavy  or  crispy 
and  minutely  serrulate  near  the  apex,  sessile  or  the  uppermost 
shortly  petioled,  2-6  inches  long  and  3-15  lines  wide,  7-17  nerved. 
Stipules  6-1 8  lines  long,  sometimes  very  broad  at  the  base,  obtuse, 
2-keeled,  loose  and  spreading  as  in  P.  JieteropJiyllns. 

Peduncles  mostly  straight  and  erect,  stout,  thicker  than  the 
stems,  sometimes  thickening  upwards,  2^-6  inches  long.  Spikes 
1-2  inches  long,  more  in  the  habit  of  fruiting  in  Europe  than  in 
this  country.  Fruit  obliquely  obovate,  i^-i^  lines  long  and 
about  i  line  wide,  the  face  usually  straight,  occasionally  a  little 
angled,  dorsally  3-keeled  in  the  mature  dried  fruit;  style  short, 
blunt,  facial;  cotyledonary  apex  nearly  touching  and  pointing 
directly  to  the  end  of  the  radicle.  The  fruit  strongly  resembles 
that  of  P.  heterophyllus. 


30 

This  species  seems  to  be  intermediate  between  P.  Jieteropliyllus 
and  P.  lucens.  It  may  generally  be  distinguished  from  the  former 
by  its  larger  size,  by  floating  leaves  of  thinner  texture  and  more 
sloping  at  the  base,  by  its  larger,  more  sharply  pointed  and 
strongly  undulate  submerged  leaves  and  larger  fruit.  From  P. 
lucens  it  may  be  distinguished  by  its  floating  leaves,  which  are 
lacking  in  P.  lucens,  as  well  as  by  its  smaller  fruit  and  other  char- 
acteristics. It  usually  sends  up  coriaceous  floating  leaves  late  in 
the  season.  It  flowers  freely,  but  seldom  fruits  in  the  United 
States.  It  commonly  occurs  in  rather  shallow  and  quiet  waters, 
but  is  not  widely  diffused. 

A  form  collected  by  Prof.  Macoun  in  Methy  Lake,  Lat.  57°  n., 
Canada,  and  which  I  have  not  seen,  is  thus  named  and  described 
by  Mr.  Bennett  in  Jour.  Bot.  for  May,  1891,  p.  151. 

"  Var.  Metkyemis.  Differs  from  any  form  of  the  type  in  America 
or  Europe  by  the  long,  narrow  middle  leaves.  The  upper  leaves 
are  oval,  semi-coriaceous,  with  long  stipules,  combining  the  habit 
of  longifolius,  Gay.  and  the  lucens  No.  607  of  Herb.  Fl.  Ingricae; 
fruit  smaller,  and  the  embryo  more  curved." 

The  type  has  been  found  in  Canada  in  the  Provinces  of  Ontario 
and  Quebec  (Macoun) ;  Fresh  Pond,  Cambridge,  Mass.  (Morong) ; 
Wenham,  Mass.  (Faxon,  Morong);  Pine  Plains,  N.  Y.  (Hoysradt); 
Lake  Cayuga,  N.  Y.  (Dudley) ;  Oneida  and  Seneca  Lake,  N.  Y. 
(Morong);  Delaware  river,  above  Phillipsburg,  N.  J.  (Porter); 
Pine  Station,  111.  (Hill) ;  Frankfort,  Mich.  (Hill) ;  Lewis  Lake, 
Wyoming  (Clifford  Richardson) ;  Montana  (Hayden  Survey) ; 
Florida  (Curtiss) ;  Texas  (Reverchon,  Wright).  Common  in  Eng- 
land and  Continental  Europe.  (Plate  XXXVII.) 

14.    POTAMOGETON  LUCENS,  L.  Sp.  PI.    126  (I/53). 

Stem  thick,  branching  below  and  often  with  masses  of  short 
leafy  branches  at  the  summit.  Destitute  of  propagating  buds  or 
glands.  Leaves  all  submerged,  elliptical  or  lanceolate,  uppermost 
often  oval,  rounded  at  both  ends  and  merely  mucronate,  usually 
acute  or  acuminate  and  cuspidate,  sessile  or  short  petioled,  2^4-8 
inches  long  and  8-20  lines  wide.  The  nerves  are  commonly  1 3,  but 
sometimes  fewer,  and  the  tips  frequently  serrulate.  They  are 
rarely  shining,  though  the  name  would  imply  otherwise.  Stipules 
1-3  inches  long,  obtuse,  bicarinate,  commonly  loose  and  spread- 


31 

ing,  sometimes  very  broad.  Peduncles  3-6  inches  long,  scarcely 
thickening  upwards.  Spikes  2-2^  inches  long,  very  thick  cylin- 
drical, fruiting  freely  late  in  the  season. 

Fruit  about  I  ]/2  lines  long  and  I  ^  lines  broad,  roundish  ;  keels 
small,  often  obscure  ;  face  usually  with  a  slight  inward  curve  at  the 
base ;  style  nearly  apical ;  apex  of  embryo  pointing  transversely 
inwards,  but  the  curve  less  than  in  No.  12. 

The  typical  form  of  our  species  approaches  most  nearly  to  the 
European  form  called  var.  ovalifolius,  M.  and  K.,  as  the  uppermost 
leaves  are  generally  oval  or  ovate  in  outline.  Those  remarkable 
forms,  so  common  in  Europe,  and  known  as  var.  cornutus,  Presl., 
var.  longifolius,  Gay,  and  var.  acuniinatns,  ScJinin.  never  occur  in 
our  country,  so  far  as  I  am  aware,  but  they  are  approached  by  the 
submerged  foliage  of  P.  Illinocnsis* 

Var.  CONXECTICUTENSIS,  Robbins,in  A.  Gray,  Man.  Ed.  5.  488 
(1867.) 

This  seems  to  be  a  good  variety,  but  very  rare.  As  stated  by 
Dr.  Robbins,  the  stems  are  flexuous,  the  leaves  acuminate,  and  the 
fruit  larger  than  in  the  type  (ij^-2  lines  long  and  about  \y2  lines 
wide),  distinctly  tricarinate  and  with  a  facial  style.  It  has  been 
found  only  in  Saltonstall's  Pond,  East  Haven,  Conn.  (Robbins), 
and  Pine  Plains,  N.  Y.  (Hoysradt).  Forms  resembling  this  were 
obtained  by  E.  Faxon  in  Lake  Dunmore,  Vermont,  but  without 
fruit. 

The  typical  lucens  is  not  very  common  in  this  country.  It 
occurs  rarely  in  Nova  Scotia  and  Ontario  (Macoun) ;  Fresh  Pond, 
Cambridge,  Mass.  (Morong) ;  Lakes  Cayuga,  Onondaga  and 
Oneida,  N.  Y.  (Dudley,  Morong.);  Pine  Station,  Indiana  (Hill). 
Attributed  to  Fla.  by  Chapman  (Chap.  Fl.) ;  and  to  Mission 
Dolores,  Cal.  by  Brewer  and  Watson  (Fl.  Cal).  It  has  also  been 
collected  by  Pringle  in  the  State  of  Michoacan,  Mex.  (No.  3327, 
wrongly  named  P.  Zizii).  Cuba  (Wright).  Common  throughout 
Europe,  Asiatic  Russia,  and  other  parts  of  Asia.  (Plate  XXXVIII.) 

*Mr.  A.  Bennett  in  his  recently  published  list  of  the  Potamogetons  in  the  Vienna 
Herbarium  (Ann.  der.  K.  K.  Naturhist.  Hoffmus.  for  1892,  p.  290),  notes  in  that 
collection  a  specimen  of  P.  longifolius,  Gay,  gathered  in  Oregon  by  Dr.  Lyall. 


32 

15-  POTAMOGETOX    PRAELOXGUS,   Wulf.    in    Rom.    Arch.    iii.    331 

(1805). 

P.flexuosus,  Schleich.  and  Wredow,  Meklenb.  Fl.  (1807). 
P.flcxicaulis,  Dethard,  in  Strelitz.  Anz.  1809.  n.  50. 

Stem  white,  flexuous,  flattened,  much  branched,  growing  in 
deep  water,  sometimes  6  to  8  feet  in  .length.  Leaves  all  sub- 
merged, oblong  or  oblong-lanceolate,  obtuse  and  cucullate  at  the 
apex,  splitting  on  pressure,  semi-amplexicaul,  of  a  bright  green 
color.  They  are  from  2  to  12  inches  in  length,  and  from  y2  to 
1 1/£  inches  wide,  with  only  3  or  5  main  and  from  7  to  17  finer 
nerves,  sometimes  with  a  narrow  reticulated  space  on  each  side  of 
the  midrib.  Stipules  white,  scarious,  obtuse  and  commonly 
closely  embracing  the  stem.  Abnormal  specimens  with  spread- 
ing stipules  2-3  inches  long  have  been  collected  in  Maine  by  Miss 
Kate  Furbish.  Peduncles  from  3  to  15  inches  and  occasionally 
as  much  as  20  inches  long,  erect,  straight,  about  as  thick  as  the 
stem,  and  often  very  numerous.  Spikes  1-2  inches  long,  thick, 
cylindrical,  densely  fruiting.  Fruit  dark  green,  obliquely  obovate, 
2,-2.y2  lines  long  and  1^-2  lines  wide;  the  back  much  rounded, 
often  with  the  upper  curve  nearly  as  high  as  the  style.  Middle 
keel  sharp  and  prominent,  sloping  on  the  sides  to  rather  obscure 
lateral  keels;  face  straight  or  nearly  so;  style  short,  obtuse,  facial; 
apex  of  embryo  pointing  directly  to  the  base. 

This  species  fruits  in  our  country  in  June  and  July,  and  usually 
withdraws  its  stems  beneath  the  water  as  soon  as  the  fruit  is  set. 
Hence  the  difficulty  of  obtaining  good  fruit  unless  dredging  is 
resorted  to. 

Deep  water,  lakes  and  ponds,  Nova  Scotia,  New  Brunswick, 
Ontario  and  Vancouver's  Island  (Macoun's  Cat.) ;  Shelburne  Pond 
Vt.  (Pringle) ;  Wenham  and  Fresh  Ponds,  Mass.  (Morong) ;  Bantam 
Lake,  Litchfield,  Conn.  (Morong) ;  Lake  Salstontall,  Conn.  (Prof.  J. 
A.  Allen);  Canaan,  Conn.  (Robbins) ;  Budd's  Lake,  N.  J. (Porter); 
Lake  Canandaigua,  N.  Y.  (Morong) ;  Maltowah  Lake  and  Chen- 
ango  River,  N.  Y.  (Coville) ;  Frankfort,  Mich.  (Hill) ;  along  the 
Great  Lakes  to  Lake  Superior  (Robbins) ;  Vermilion  Lake,  Minn. 
(L.  H.  Bailey);  Iowa  (Arthur's  Cat.);  National  Park  (Clifford 
Richardson);  Sierra  Co.,  Cal.  (Brew,  and  Wats.  Bot.  Cal.).  (Plate 
XXXIX.) 


33 

l6.    POTAMOGETON   PERFOLIATUS,  L.  Sp.  PI.   126  (1/53). 

Stems  slender,  from  running  rootstocks  which  throw  up  many 
shoots,  much  branched,  often  with  many  short  lateral  branches 
along  the  main  stem.  Leaves  very  variable  in  shape  and  size, 
mostly  ovate  or  rounded,  sometimes  lanceolate,  usually  obtuse, 
sometimes  acute  at  the  apex,  amplexicaul  and  cordate  at  base, 
meeting  around  the  stem.  They  are  never  cucullate,  as  in  the 
preceding  species,  and  never  known  to  produce  propagating  buds 
or  glands.  They  are  often  crowded  upon  the  stem,  but  more 
commonly  separated  at  a  considerable  distance,  generally  alter- 
nate, but  opposite  under  the  nodes  of  the  branches.  The  typical 
European  forms  have  large  rounded  or  ovate  leaves  about  2  inches 
long  by  \l/2,  inches  broad,  varying  from  this  to  narrow  and  elon- 
gated forms  l/>-\%  inches  long  and  4-15  lines  in  width,  and  13- 
27-nerved.  The  full  type  is  rather  rare  in  this  country,  the  greater 
part  of  our  forms  being  small  leaved,  and  west  of  New  England  run- 
ning into  the  form  known  as  Var.  lanccolatus,  Robbins.  As  found 
here  the  typical  plant  has  leaves  varying  from  5  to  1 5  lines  long 
and  from  3  to  12  lines  wide,  usually  obtuse  and  minutely  serrulate 
near  the  apex.  Peduncles  I  j^  inches  long,  about  the  same  thick- 
ness as  the  stem,  usually  erect  or  slightly  spreading,  running  in  the 
axils  of  the  leaves  for  a  long  distance  along  the  upper  part  of  the 
stem.  Spikes  8-12  lines  long,  often  flowering  and  fruiting  under 
water.  Fruit  obliquely  obovate,  i^-i^  lines  long  by  I  line  or  a 
little  more  in  breadth,  obscurely  tricarinate  on  the  back,  the  face  a 
little  curved  outwardly  towards  the  top,  the  sides  \vith  a  shallow 
indentation  which  runs  into  the  face  ;  style  nearly  facial ;  embryo 
slightly  incurved  or  with  its  apex  pointing  directly  towards  the 
base. 


Var.  RICHARDSONII,  Ar.  Bennett,  Jour.  Bot.  xxvii.  25  (i! 
Var.  lanceolatits,  Robbins,  in  A.  Gray,  Man.  Ed.  5,  488  (1867). 

Mr.  Bennett  notes  that  the  name  of  Robbins  is  preoccupied  by 
a  different  form  of  Blytt  in  Norges  Flora  (1861),  and  proposes  the 
present  name  in  honor  of  the  Arctic  explorer,  Dr.  Richardson, 
"  who  seems  to  have  been  the  first  to  point  out  the  difference  from 
the  European  forms  in  the  '  Appendix '  (Botany)  to  Franklin's  Ex- 
pedition." 


34 

Leaves  of  this  variety  lanceolate,  from  i  to  4^  inches  long  and 
4-8  lines  wide  at  the  broadened  amplexicaul  base,  often  curving 
inwards  towards  the  apex,  and  from  13  to  23-nerved.  Leaves 
from  North  Hero,  Lake  Champlain  (Morong),  and  Sault  Ste. 
Marie,  St.  Mary's  River,  Mich.  (Hill),  measuring  4^  inches  in 
length,  are  the  longest  that  I  have  ever  seen.  The  fruit  is  some- 
what larger  than  in  the  type,  measuring  about  i  ^  lines  long  by 
I  *^  lines  wide. 

Forms  found  in  Wenham  Pond,  Mass.,  greatly  resemble  P. 
nitcns,  Webber,  of  Europe,  and  are  considered  to  be  this  species 
by  Dr.  Tiselius.  They  also  bear  a  strong  resemblance  to  P.  per- 
foliatus,  var.  Jacksoni,  Nees,  of  England,  which  is  regarded  as  a 
form  of  nitens  by  Prof.  Babington.  They  have  oblong  leaves  i- 
\y2  inches  long  and  4-9  lines  wide,  obtuse,  7-i3-nerved,  not  ser- 
rulate, semi-amplexicaul,  with  very  slender,  laterally  much-branched 
stems. 

Common  in  Canada  from  Nova  Scotia  to  Ontario  (Macoun). 
In  the  United  States  it  occurs  in  nearly  all  parts  of  the  country 
from  Maine  to  Florida,  and  west  to  the  Pacific.  The  variety 
occurs  in  Ontario,  Canada,  and  thence  westward,  and  from  Lake 
Champlain,  Eastern  New  York  and  Delaware  westward  to  Oregon 
and  California,  being  the  most  common  Western  form.  In  still, 
shallow  or  deep  water.  July-September.  (Plate  XL.  Var.  Rich- 
ardsonii  is  figured  on  the  right). 

17.  POTAMOGETON  MvsTicus,  Morong,  Bot.  Gaz.  5,  50  (1880). 

Whole  plant  very  slender  and  delicate.  Stems  from  a  creep- 
ing rootstock  which  throws  up  many  shoots,  irregularly  branching 
above,  nearly  filiform,  terete,  1-3  feet  high.  Leaves  all  submerged, 
scattered,  oblong-linear,  \-\y>  inches  long  and  1-3  lines  wide, 
5-7-nerved,  obtuse  and  rarely  with  minute  serrulations  near  the 
apex,  abruptly  narrowing  at  the  base  and  sessile  or  partly  clasping. 
Stipules  obtuse,  about  6  lines  long,  hyaline,  with  many  fine  nerves, 
mostly  deciduous,  but  sometimes  persistent  and  closely  sheathing 
the  stem.  Spikes  few,  capitate,  4-6-flowered,  on  erect  peduncles 
from  i  to  2  inches  in  length.  No  ripe  fruit  has  ever  been  found, 
but  one  or  two  immature  drupes  indicate  that  it  is  obovate,  min- 
ute, scarcely  ^  of  a  line  long  by  l/2  a  line  broad,  obscurely  3- 
keeled  on  the  back,  a  little  beaked  by  the  slender  recurved  style. 


35 

Since  I  obtained  this  from  Mystic  Pond,  Medford,  Mass.,  in  1879, 
I  have  visited  the  locality  for  several  years  in  succession,  and, 
though  I  have  always  found  the  plant  growing  vigorously,  yet  it 
has  shown  no  signs  of  prefecting  fruit.  In  the  year  1887  I  found 
it  growing  in  Miacomet  Pond,  Nantucket,  under  water  about  3 
feet  deep,  but  it  was  entirely  without  flowers  or  fruit. 

It  is  closely  allied  to  P. perfoliatus  in  habit,  with  which  it  is  asso- 
ciated in  growth,  but  very  unlike  that  in  foliage,  and  scarcely  one- 
third  as  stout  in  any  of  its  parts.  August-September  (Plate  XLI). 

1 8.  POTAMOGETON  CONFER vo I DES,  Reichb.  Icon.  Fl.  Germ.  et.  Helv. 

vii.  13  (1845)- 
P.  trichoides,  A.  Gray,  Man.  ed.   I   p.  457  (1848).  Tuckerm.  Am. 

Jour.  Art  and  Sci.  2  ser.  vii,  358  (1849),  not  Cham. 
P.  Tuckermani,  Robbins  in  A.  Gray,  Man.  Ed.  2.  434  (1856). 

Mr.  Bennett  states  in  Jour.  Bot.  xxviii.  92,  that  he  has  seen  a 
specimen  of  this  species  in  Gay's  Herb,  at  Kew  under  Reichen- 
bach's  name,  and  that  it  is  undoubtedly  the  same  as  P.  Tuckermani, 
Robb.  The  description  of  Reichenbach  corresponds  very  well  to 
our  plant.  There  is  here  a  good  illustration  of  the  danger  of  determin- 
ing names  without  corroborating  specimens,  for  Tuckerman,  one  of 
the  most  minute  and  careful  observers,  says  in  his  paper  upon  P. 
triclioidcs:  "I  have  seen  no  specimens  of  the  European  plant,  but 
Chamisso's  minute  description,  and  his  figure  of  the  fruit  leave  little 
or  no  doubt  of  the  identity  of  ours  with  it,"  and  yet  he  was  mis- 
taken. 

Stem  from  a  creeping  rootstock,  slender,  terete,  much-branched, 
the  upper  branches  repeatedly  dichotomous,  6-18  inches  high. 
Leaves  very  delicate,  flat,  setaceous,  \-2l/2  inches  long,  the 
broadest  scarcely  %.  nne  wide,  tapering  to  a  long  hair-like  point, 
i-3-nerved,  often  with  a  few  cross  ribs  or  coarse  reticulations,  of  a 
bright  green  color,  a  little  yellowish  tinted.  Stipules  delicate, 
obtuse,  2-3  lines  long.  Peduncles  terminal,  2-8  inches  long,  straight 
and  erect,  somewhat  thickened  upwards,  sometimes  with  a  short 
lateral  branch  bearing  a  spike.  Spikes  capitate,  3  or  4  lines  long; 
Fruit  thick  with  a  shell  roundish-obovate,  i-i  yz  lines  long  and  about 
as  wide ;  back  sometimes  a  little  angular  or  sinuate,  3-keeled,  the 
middle  keel  sharp  and  prominent ;  face  notched  near  the  base ; 
sides  impressed  with  a  shallow  indentation  which  runs  into  the 


36 

notch  of  the  face ;  style  short,  apical ;  embryo  circle  complete,  the 
apex  nearly  touching  the  base  a  little  inside  of  its  end. 

A  rare  species  growing  in  the  shallow  water  of  ponds.  Round 
Pond,  York,  Me.  (Fernald);  Franconia  Notch,  N.  H.  and  a  small 
pond  on  Mt.  Willey,  3,003  feet  alt.  (Faxon);  Uxbridge,  Mass. 
(Robbins,  Morong) ;  New  York  (Torrey)  ;  common  in  N.  J.;  Great 
Lake,  Carbon  Co.,  Pa.  (Porter).  (Plate  XLII.) 

19.  POTAMOGETON  CuRTissn,  Morong,  Bull.  Torr.  Bot.  Club,  xiii. 

145  (1886). 

Stems  simple  or  branched,  capillary,  a  foot  or  more  in  height, 
the  internodes  long  and  naked.  Leaves  6-17  lines  long,  almost 
setaceous,  many  of  them  less  than  ^  of  a  line  and  none  y2  a  line 
broad,  tapering  to  a  long,  hair-like  point,  the  midrib  with  2  deli- 
cate nerves  or  a  loosely-reticulated  space  on  each  side  of  it. 
Stipules  hyaline,  obtuse,  3  or  4  lines  long,  deciduous.  Peduncles 
3-6  lines  long,  somewhat  clavate,  erect,  axillary  and  racemosely 
disposed,  5  or  *  more  of  them  at  intervals  of  one  or  two  inches 
along  the  upper  part  of  the  stem.  Spikes  capitate,  2  or  3  lines 
long,  3-6-flowered.  Fruit  not  seen. 

Collected  by  Mr.  A.  H.  Curtiss  in  Blackwater  River,  and  a 
"  tidal  creek"  in  Northwest  Florida,  May  and  June,  1886,  the  only 
known  locality  for  it.  (Plate  XLIII.  A  magnified  leaf  is  figured 
on  the  right.) 

20.  POTAMOGETON  CRISPUS,  L.  Sp.  PI.  126  (1753). 
Stems  branching,  compressed.  Leaves  2-ranked,  linear-oblong 
or  linear-oblanceolate,  sloping  at  base,  sessile  or  semi-amplexicaul, 
obtuse,  serrulate,  crisp,  ^-4  inches  long  and  3-7  lines  wide,  3-7- 
nerved,  the  midrib  often  compound  and  the  outer  nerves  very  near 
the  margin.  Stipules  small,  scarious,  obtuse,  early  perishing. 
Peduncles  1-2  lines  long,  frequently  recurved  when  in  fruit  and 
sometimes  very  numerous.  Spikes  about  half  an  inch  long,  and 
looking  very  bristly  with  the  long-beaked  drupes  when  in  fruit. 
Fruit  ovate,  about  \l/2  lines  long  and  I  line  or  a  little  more  in 
width,  having  3  rounded  keels  on  the  back,  the  middle  one  with  a 
small  projecting  tooth  near  the  base,  a  slightly  curved  face,  and  a 
curved  facial  style  nearly  as  long  as  the  drupe  ;  the  shell  thick  and 
corky,  containing  a  small  embryo,  the  apex  of  which  points 
directly  towards  the  end  of  the  radicle. 


37 

This  species  in  our  country  propagates  itself  mainly  by  winter 
buds,  of  which  there  are  two  kinds.  The  rarer  kind  is  spicular  in 
form,  being  simply  a  fragment  of  the  stem,  shrunken  or  sharpened 
at  the  ends,  with  2-6  buds  upon  it  in  the  axils  of  the  decayed 
leaves.  The  more  common  form  is  a  thick,  rigid  body  composed 
of  the  ends  of  the  branches  or  stems,  in  which  the  upper  portion 
is  swollen,  hardened  and  surrounded  by  the  bases  of  the  leaves, 
which  are  also  much  enlarged  and  indurated,  and  reduced  to  a 
triangular  shape,  several  buds  being  left  in  the  axils.  The  lower 
end  becomes  sharpened  and  is  so  easily  detached  that  a  mere  jar 
shakes  it  off  the  stem.  The  whole  bud  looks  like  a  burr,  and  when 
separated  from  the  stem  floats  away  bottom  side  up  or  sinks  into  the 
mud .  The  new  plant  is  formed  by  the  development  of  one  of  the  buds 
which  throws  out  .roots  as  it  grows.  It  occurs  in  fresh  and  brackish 
or  tide  water.  Confined  to  a  strip  along  the  Atlantic  coast  from 
Arlington,  Mass.,  to  James  City,  Virginia.  It  also  runs  inland  in 
fresh  water  as  far  as  Lancaster,  near  the  Susquehanna  River,  Pa. 
(Porter),  and  the  Lakes  Keuta  and  Seneca,  in  the  centre  of  New 
York.  Introduced  from  Europe,  where  it  is  common.*  (Plate 
XLIV.  The  two  kinds  of  propagating  buds  are  shown  on  the 
left.) 

21.  POTAMOGETON   zosTER/EFOLius,  Schum.  Enum.  PI.  Saell.  50, 

168  (1801). 

P.  cojnplanatns,  Willd.  Mag.  Berl.  Fl.  iii.  248  (1809). 
P.  coinpivssus,  Fries,  Nov.  Ed.  2.  44  (1828),  not  L.  Herb. 
P.  cuspidatus,  Schrad.  in  Smith's  Eng.  Bot.  i.  235  (1828). 

Stem  very  much  flattened,  sometimes  winged,  widely  branch- 
ing. Leaves  linear,  obtuse  and  mucronate  or  shortly  acute,  with 
3  principal  nerves  and  many  fine  ones,  the  midrib  often  compound, 
2-12  inches  long  and  1-2  inches  wide.  Stipules  scarious,  obtuse, 
finely  nerved,  soon  perishing.  Peduncles  i  ^-4  inches  long ; 
spikes  cylindrical,  about  y2  inch  long,  12-15  flowered.  Fruit 
obovate,  with  a  broad  base,  1^-2  lines  long  and  \%-\y2  lines 
wide,  3-keeled  on  the  back,  lateral  keels  somewhat  obscure,  the 


*  Probably  of  recent  introduction,  as  it  seems  not  to  have  been  known  to  the 
older  botanists,  Rafinesque,  Michaux,  Pursh,  Xuttall,  Barton  and  others  who  col- 
lected extensively  in  the  region  where  it  grows  during  the  early  part  of  this  century. 


middle  one  often  slightly  toothed  or  undulate  and  with  a  projec- 
tion at  the  base;  face  arched,  beaked  with  a  short,  recurved  style; 
embryo  slightly  incurved. 

The  propagating  buds  of  this  species  are  very  unlike  those  of 
No.  2O,  consisting  only  of  the  ordinary  terminal  leaf  bud  which 
drops  off  near  the  end  of  the  branch,  sinks  to  the  bottom  and  rests 
in  the  mud  during  the  winter.  It  is,  however,  a  very  common 
source  of  propagation. 

An  elegant  plant,  with  bright  smooth  leaves  in  fascicles  at  the 
summits  of  the  branches.  It  may  be  distinguished  from  other 
North  American  species,  and  from  Heteranthcra  graminea  with 
flowerless  forms  of  which  it  is  sometimes  confounded,  by  the  nu- 
merous fine  nerves  on  the  leaves. 

In  still  or  slowly  moving  water  in  Northern  regions.  New 
Brunswick  to  the  Saskatchewan,  Canada  (Macoun);  Vermont  to 
New  Jersey  and  westward  to  Iowa,  Lake  Superior  and  Oregon 
(Hall,  No.  491,  fide  Brew,  and  Wats.  Bot.  Cal.\  Common  in 
Europe.  July,  August.  (Plate  XLV.) 

22.  POTAMOGETON  HiLLii,  Morong,  Bot.  Gaz.  vi.  p.  290  (1881). 

Stems  slightly  compressed,  slender,  widely  branching,  1-2  feet 
in  height.  Leaves  linear,  acute  or  abruptly  acute  and  cuspidate, 
often  almost  aristate,  i-2}/£  inches  long  and  y2-i  %  lines  wide,  3- 
nerved,  the  lateral  nerves  delicate  and  nearer  the  margins  than  the 
midrib,  the  midrib  below  often  compound.  Stipules  whitish, 
many-nerved,  obtuse,  3-5  lines  in  length.  Peduncles  about  half 
an  inch  long,  erect  or  slightly  recurved,  more  or  less  clavate. 
Spikes  capitate,  3-6  fruited.  Fruit  obliquely  obovate,  obtuse  at 
the  base,  1^-2  lines  long  by  i-i  */£  lines  broad,  tricarinate  on  the 
back,  the  middle  keel  sharp  and  more  or  less  undulate,  flat  on  the 
sides,  the  face  slightly  arched ;  style  nearly  facial,  short,  recurved ; 
embryo  apex  pointing  transversely  inwards. 

There  are  two  forms  of  this  species,  the  one  biglandular  at  the 
base  of  the  leaves,  and  the  other  glandless.  I  found  it  growing  in 
the  small  pot  ponds  of  Manistee,  Mich.,  each  pond  having  its  own 
form  and  apparently  never  mixing.  In  general  appearance  similar 
to  the  large  forms  of  P.foliosus,  but  allied  by  its  peduncles,  spikes 
and  fruit  to  P.  obtusifolius  and  P.  zostcrafolius ,  and  still  more 


39 

closely  to  the  European  P.  acntifolius,  Link,  to    which    in  these 
respects  it  bears  a  close  resemblance. 

A  rare   species  growing  in  pools  and  ponds,  and  so    far   as 
known,  peculiar  to  the  United  States.     Lake  Cayuga  and  near  Free- 
ville,  N.  Y.  (Dudley);   Pine  Plains,  N.  Y.  (Hoysradt) ;  Manistee, 
Mich.  (Hill,  Morong);  Ashtabula,  Ohio  (Hill).     (Plate  XLVI.) 
23.  POTAMOGETON  FOLiosus,  Raf.  Med.  Rep.  2d  Hex.  v.  354(1808). 
P.  gramincus  ?  MX.  Fl.  i.  102  (1803),  not  L. 
P.  pauciflorus,  Pursh,  Fl.  i.  121  (1814). 

Pursh's  name,  which  this  species  has  borne  so  long,  must  be 
surrendered,  not  only  because  it  had  been  antedated  by  that  of  Raf- 
inesque,  but  also  because  it  had  been  used  by  Lamark  as  long  ago 
as  1 778  (Fl.  Franc,  iii.  209,  No.  798)  as  a  synonym  of  P.  densus,  L. 

A  variable  species  peculiar  to  North  America.  Stems  flat- 
tened, much-branched,  i  to  3  feet  high.  Leaves  1-2  inches  long 
and  i^-i  line  wide,  acute,  3-nerved,  not  glandular  at  the  base. 
Very  delicate  forms  are  found,  especially  near  the  Atlantic  coast, 
which  are  scarcely  more  than  6  inches  in  height,  the  stems  fili- 
form, the  leaves  not  over  8  lines  long  by  %  line  wide,  the  lateral 
nerves  obscure  or  even  obsolete.  From  this  it  rises  into  the 
coarser  forms  which  are  more  common  inland  and  towards  the 
west.  Stipules  white,  hyaline,  obtuse,  sometimes  acute,  6-10  lines 
long.  Peduncles  more  or  less  club-shaped,  erect,  about  l/2  inch 
long.  Spikes  about  4-flowered.  Fruit  impressed  with  a  shallow 
pit  on  each  side  when  young,  but  even  when  fully  mature,'  lenticu- 
lar, or  nearly  orbicular,  3^-1  line  in  diameter;  3-keeled  on  the 
back,  the  middle  keel  winged,  sinuate-dentate,  often  with  project- 
ing shoulders  or  teeth  at  each  end ;  face  strongly  angled  or  arched, 
sharp  or  alate,  often  with  a  sharp,  projecting  tooth  at  the  base; 
style  nearly  apical,  straight  or  recurved  ;  embryo  curve  complete, 
the  apex  nearly  touching  the  basal  end.  The  fruit  rarely  ap- 
proaches that  of  P.  pusillus,  being  obliquely  obovate,  about  i  line 
long  and  3^  line  wide,  the  wing  on  the  middle  keel  narrow  and 
not  dentate,  but  still  it  may  always  be  distinguished  by  being  more 
or  less  crested.  This  species  is  also  in  very  rare  cases  furnished 
with  reproductive  buds  and  minute  glands  like  those  of  pnsillus. 
Var.  NIAGAKKNSIS  (Tuckerman)  A.  Gray,  Man.  ed.  2.  435  (1856). 
P.  Niagarciisis,  Tuckerm.  Am.  Jour.  Sci.  2  ser.  vii.  354  (1849). 


40 

Larger  than  the  type,  stems  2-3  feet  in  height,  leaves  some- 
times over  3  inches  in  length  and  I  line  wide,  3-5 -nerved. 
Stipules  longer  and  occasionally  acute.  Spikes  8-12  flowered. 
Mainly  distinguished  by  its  large  size.  This  form,  which  is  the 
coarsest  in  the  species,  was  originally  discovered  by  Prof.  Tucker- 
man  in  the  rapids  above  Niagara  Falls,  and  was  considered  by  him 
a  good  species,  but  it  seems  to  me  too  near  foliosus  to  take 
specific  rank.  For  many  years  it  seemed  to  have  disappeared 
from  the  original  locality  until  the  writer  found  it  in  abundance  in 
a  sluice  way  between  the  Falls  and  the  village  on  the  American 
banks.  It  has  recently  been  collected  by  Mr.  F.  V.  Coyille  in  the 
United  States  expedition  to  Death  Valley,  California. 

Var.  CALIFORNICUS,  Morong,  Bot.  Gaz.  x.  254  (1885). 

This  form  is  distinguished  by  its  bushy,  vigorous  growth  and 
large  thick  stem  which  is  strongly  flattened  and  sometimes  winged, 
often  y2  line  wide.  Many  stems,  thickly  clustered,  rise  from  the 
roots.  Leaves  not  so  long  or  broad  as  in  the  preceeding  variety, 
but  with  a  dilated  mid-rib,  reminding  one  of  P.  obtusifolius,  and 
frequently  5-nerved  at  the  base.  Peduncles  4-6  lines  long,  erect, 
clavate,  flattened.  Spikes  often  ripening  12  strongly  marked  fruit. 
Collected  in  San  Bernardino  county,  Cal.  by  the  Parish  Brothers, 
and  by  D.  Cleveland  at  San  Diego. 

The  species  has  a  wide  range,  occurring  in  Canada  from  New 
Brunswick  to  British  Columbia  (Macoun);  New  England  to  Florida 
and  New  Mexico  and  westward  to  Oregon  and  California.  July- 
September.  (Plate  XLVII.  Two  common  forms  of  the  fruit  are 
figured.) 

24.  POTAMOGETON  OBTUSiFOLius,  M.  and  K.  Deut.  Fl.  i.  855  (1823). 
P.  gramineus,  Sowerby,  Eng.  Bot.  iii.  t.  2253  (1794),  not  L. 
P.  compressus,  Wahl.  Fl.  Suec.  i.  p.  107  (1824),  not  L. 

Stem  usually  slender,  compressed,  branching  widely,  especially 
towards  the  summit.  Leaves  linear,  2-3  inches  long  and  y2-2, 
lines  wide,  obtuse,  often  mucronate,  usually  3-nerved,  sometimes 
5-  and  rarely  7-nerved,  biglandular  at  base,  the  glands  large  and 
translucent,  the  midrib  broad  and  frequently  compound.  Stipules 
white  or  scarious,  many-nerved,  obtuse,  6-9  lines  long,  often  as 
long  as  or  longer  than  the  internodes.  Peduncles  numerous,  y2— 


41 

i  y2  inches  long,  slender,  erect,  rising  from  the  axils  of  the  branches. 
Spikes  3-4  lines  long,  ovate,  continuous,  5-8  flowered.  Fruit 
obliquely  obovate,  about  \]/2  lines  long  and  I  line  wide,  3-keeled, 
middle  keel  distinct;  face  straight  or  nearly  so;  sides  with  a  slight 
impression  which  runs  into  the  face;  style  short,  blunt,  nearly 
facial ;  embryo  with  the  apex  pointing  a  little  inside  of  the  base. 
In  North  American  forms  the  fruit  is  slightly  longer  and  narrower, 
and  the  embryo  more  incurved  than  in  the  European  plant. 
Rarely  producing  propagating  buds. 

Non-fruiting  specimens  of  P.  major  are  liable  to  be  con- 
founded with  this  species.  For  the  distinctions  see  under  that 
species. 

Not  very  common  in  this  country.  Ponds  and  still  waters. 
Quebec  and  Methy  River,  Lat.  57°  N.  Canada  (Macoun); 
Barton,  Vt.  (Robbins);  Granby,  Mass.  (Tuckerman);  Pleasant 
Pond,  Wenham,  Mass.  (Morong);  Worcester  and  Natick,  Mass. 
(Morong);  Pine  Plains,  N.  Y.  (Hoysradt);  Spencer,  N.  Y.  (Dud- 
ley); Easton  and  Susquehanna  River,  Pa.  (Porter);  Lake  Superior 
(Robbins);  Vermilion  Lake,  Minn.  (L.  H.  Bailey);  Sherburne 
Geyer  Basin,  Wyoming  (Clifford  Richardson).  July-August 
(Plate  XLVIII.) 

25.  POTAMOGETON  MAJOR  (Fries)  Morong. 

P.  pusilllns  L.  var.  major >  Fries,  Nov.  48  (1828).' 

P.  Friesii,  Ruprecht  in  Beit.  Pf.  de  Russ.  R.  iv.  43  (1845). 

P.  compresses,  Sm.  Eng.  Bot.  iii.   t.  418  (1794).     Reich.  Ic.  Fl. 

Germ.  vii.  15  (1845),  not  L. 

The  name  compresus,  which  is  used  by  some  authors  must  be 
discarded,  because  it  is  applied  by  Linnaeus  himself  to  several 
species.  P,  mncronatus,  Schrad.,  is  also  uncertain,  according  to 
Mr.  Bennett,  who  has  carefully  studied  the  synonymy  of  this 
species.  (See  Journ.  Bot.  May,  1891,  p.  150).  Fries'  varietal 
name,  so  far  as  I  can  see,  is  the  earliest  name  applied  to  it  on  which 
we  can  depend. 

Stems  compressed,  2-4  feet  high,  branching,  Leaves  I  ^-2  */£ 
inches  long,  about  I  line  wide,  shortly  acute  or  obtuse  and  cuspi- 
date, usually  5 -nerved,  but  rarely  7-nerved,  biglandular  at  base, 
the  glands  small,  often  dull.  Intermediate  forms  between  this  and 
P.pusillus  often  occur  in  this  country  in  which  most  of  the  leaves 


42 

are  3-nerved  or  5 -nerved  at  the  base  only.  Stipules  white,  hyaline, 
finely  nerved,  obtuse  or  acute,  6-12  lines  long.  Peduncles  i-il/2 
inches  long,  often  thicker  than  the  stem  and  sometimes  thickening 
upwards.  Spikes  when  developed  interrupted.  Fruit  quite  simi- 
lar to  that  of  P.  pusillus,  but  I  find  it  always  with  a  recurved  style, 
generally  with  a  shallow  pit  on  the  sides  and  with  the  apex  of  the 
embryo  pointing  almost  directly  towards  the  basal  end.  The  pro- 
pagating buds  are  similar  to  those  of  P.  pusillus,  but  not  so 
common. 

This  species  may  generally  be  distinguished  from  pusillus  in 
its  various  forms  by  its  larger  leaves,  larger  and  more  flattened 
stems  and  its  more  elongated  and  less  branching  habit,  but  the 
two  run  together  so  closely  that  at  times  it  is  difficult  to  separate 
them.  It  is  considered  by  some  authors  as  intermediate  between 
P.  pusillus  and  P.  obtusifolius,  and  when  not  in  fruit  it  may  be  con- 
founded with  the  latter,  but  as  a  rule  the  glands  are  smaller  and 
duller  in  tint  than  in  that,  and  the  leaves  shorter.  P.  obtusifolius, 
too,  is  much  more  bushy  in  habit,  sometimes  even  spreading  out 
in  fan-shape,  and  it  is  extremely  rare  that  its  leaves  have  more 
than  3  nerves. 

The  species  rare  in  the  United  States.  New  Brunswick,  On- 
tario and  British  Columbia  (Macoun);  Lake  Champlain,  Vt. 
(Faxon) ;  Lake  Seneca,  N.  Y.,  abundant  (Morong) ;  Wisconsin 
(Lapham);  Michigan  (Hill);  Minnesota  (Cratty).  July-Septem- 
ber. (Plate  XLIX.  A  leaf  magnified  is  shown  on  the  left.) 

26.   POTAMOGETON  RUTiLUS,  Wolfg.  in  R.  and  S.  Mant.  iii.    362 

(1827). 
P.  caspitosus,  Nolte,  fide  Reich.  Ic.  vii.  15. 

Stems  very  slender,  8  to  24  inches  in  height,  compressed;  roots 
finely  fibrous,  sending  up  many  stems,  but  each  stem  simple  or 
nearly  so.  I  find  them  occasionally  rising  from  a  bit  of  stem  or 
hybernaculum,  showing  that  the  species  is  sometimes,  at  least, 
propagated  in  this  way,  but  usually  without  propagating  buds. 
Leaves  I  to  I  y2  inches  long  and  ^  to  y2  a  line  broad,  acute  or 
acuminate,  strict,  nearly  erect,  3-5  nerved,  revolute,  nerves  promi- 
nent beneath,  the  midrib  compound,  especially  at  the  base,  where 
it  often  divides  into  2  and  even  4  strongly  marked  nerves,  often 


43 

biglandular  at  base  and  bright  green  in  color.  Stipules  acute,  6- 
10  lines  long,  often  longer  than  the  internodes  and  hiding  the 
bases  of  the  leaves  above,  persistent,  becoming  white  and  fibrous 
with  age.  Peduncles  6-18  lines  long,  scarcely  thicker  than  the 
stems.  Spikes  3-5  lines  long,  usually  continuous,  but  sometimes 
interrupted.  Fruit  obliquely  obovate,  ^-i  line  long  by  ^-% 
line  wide,  keels  obscure,  or  the  back  showing  only  2  small  grooves; 
face  obtusely  angled  towards  the  base;  apex  of  drupe  sloping  into 
a  short,  facial,  recurved  style;  embryo  circle  not  complete,  the  apex 
pointing  a  little  inside  of  the  basal  end.  Resembling  pusillns, 
especially  those  occasional  forms  of  that  species  which  have  acute 
and  somewhat  revolute  leaves;  but  its  strict,  almost  or  quite  erect 
leaves  with  long  very  sharp  acuminate  points,  prominent  nerves, 
and  long,  persistent,  acute  stipules  well  distinguish  it. 

A  rare  species  in  this  country.  Anticosti,  at  the  mouth  of  the 
Nipigon  River,  near  Red  Rock,  Lake  Superior  and  James  Bay, 
Canada  (Macoun).  Found  by  Prof.  L.  H.  Bailey  in  flower  July  24, 
1886,  in  Vermilion  Lake,  Minn.,  (no.  B.  394).  (Plate  L.) 

27.  POTAMOGETON  VASEYi,  Robbins,  in  A.  Gray.  Man.  Ed.  5,  485 

(1867). 

Bearing  floating  leaves  on  the  fertile  stems  only.  Very  deli- 
cate, stems  filiform,  widely  branching  from  below  and  with  many 
short  lateral  branches  above,  i-i^  feet  in  height.  The  emersed 
fertile  forms  in  shallow  water,  near  shore,  and  the  more  common 
sterile  submerged  forms  in  water  from  6  to  8  feet  in  depth.  Float- 
ing leaves  coriaceous,  in  1-4  opposite  pairs  at  the  top  of  the  stem, 
the  blades  obovate,  4-5  lines  long  by  2-3  lines  wide,  with  5-9 
nerves  deeply  impressed  beneath,  sloping  at  base  into  petioles  3-4 
lines  long.  Submerged  leaves  almost  capillary,  nerveless  or  i- 
nerved,  tapering  to  the  fineness  of  a  hair,  i-i^  inches  in  length. 
The  leaves  frequently  biglandular  at  base.  Stipules  white,  delicate, 
many  nerved,  acute  or  obtuse,  2-3  lines  long.  Peduncles  3-6 
inches  long,  spreading  or  recurved,  thickening  in  fruit.  Spikes 
2-3  lines  long,  often  interrupted.  Fruit  roundish-obovate,  about  i 
line  long  and  nearly  as  broad,  3-keeled,  middle  keel  rounded ;  face 
arched  above  and  incurved  below,  tipped  with  a  rather  long 
straight  or  recurved  style;  sides  even  or  impressed  with  a  shallow 


44 

pit.  The  spikes  ripen  from  2  to  6  fruit,  most  of  the  flowers  being 
abortive.  This  species,  especially  in  the  submerged  plant,  is  fur- 
nished with  delicate  reproductive  buds  which  are  formed  at  the 
ends  of  short  lateral  branches  and  by  which  it  seems  to  be  mainly 
propagated.  The  internodes  are  usually  long  and  naked. 
Var.  LATIFOLIUS,  Morong. 

A  rare  form  with  submerged  leaves  ^-^4  of  a  line  wide, 
abruptly  acute  and  i-3-nerved.  The  glands  more  conspicuous 
than  in  the  type.  This  was  collected  by  Dr.  Beardsley  at  Paines- 
ville,  Ohio. 

A  rare  endemic  species  confined  to  Canada  and  the  Northern 
United  States. 

The  original  plant  was  collected  by  Dr.  George  Vasey  near 
Ringwood,  Ohio.  It  has  since  been  found  at  Ottawa  (Fletcher), 
and  on  the  Great  Plains,  Canada  (Macoun) ;  Barnet,  Vt.  (Dr. 
Blanchard);  Lake  Saltonstall,  Conn.  (O.  D.  Allen);  Spot  Pond, 
Stoneham,  Mass.,  Lake  Quinsigamond,  Worcester,  Mass,  and 
Greenwood  Lake,  N.  Y.  (Morong).  (Plate  LI.) 

28.  POTAMOGETOM  LATERALis,  Morong,  Bot.  Gaz.  v.  51  (1880). 

Stems  filiform,  much-branched,  internodes  usually  long  and 
naked.  Floating  leaves  coriaceous,  elliptical,  obtuse  at  the  apex 
and  sloping  at  base  into  petioles  3-10  lines  long,  blades  4  or  5 
lines  long  by  1-2  lines  broad,  with  5-7  nerves  deeply  impressed 
beneath,  usually  in  1-3  opposite  pairs  which  stand  at  right  angles 
to  the  stem,  found  only  on  sterile  shoots.  Submerged  leaves  very 
narrow,  linear,  acute,  1-3  inches  long  and  y^-Y*  lme  wide,  1-3- 
nerved,  the  lateral  nerves  very  delicate  and  obscure,  the  midrib 
prominent  and  often  with  fine  veins  or  cellular  reticulations  on 
each  side  of  it,  biglandular  at  base,  but  the  glands  few,  small 
and  often  obsolete.  Stipules  small,  hyaline,  many-nerved,  obtuse, 
deciduous.  Peduncles  as  well  as  the  floating  leaves  with  a  pecu- 
liar lateral  appearance,  widely  spreading  at  maturity,  sometimes 
even  recurved,  thickened  when  in  fruit,  4-15  lines  in  length. 
Spikes  capitate  or  often  interrupted,  3-4-flowered.  Fruit  obliquely 
obovate,  about  i  line  long  by  ^  line  broad,  lenticular,  the  back 
much  curved  and  2-grooved,  the  face  arched  and  surmounted  by 
the  nearly  sessile  stigma ;  embryo  oval  in  its  curve,  the  apex 


45 

nearly  touching  the  point  of  the  base.  The  plant  is  scantily  fur- 
nished with  reproductive  buds  like  those  of  P.  pusillus.  Proliferous 
shoots  at  the  summit  of  the  stem  and  on  the  upper  branches, 
above  the  floating  leaves,  appear  late  in  the  season  just  as  the 
plants  are  beginning  to  decay,  a  very  peculiar  habit. 

In  slowly-moving  water,  3-4  feet  deep,  in  dense  masses, 
Charles  River,  Dedham,  Mass.  (Faxon,  Morong) ;  Salisbury, 
Conn.  (Robbins);  Hemlock  Lake,  Livingstone  Co.  N.  Y.,  and 
Bear  Lake,  Mich.  (Hill).  July,  August.  (Plate  LII.  Sterile  and 
fertile  branches.) 

29.    POTAMOGETON  PUSILLUS,  L.  Sp.  PI.   I  2J  (l/53). 

A  variable  species  with  filiform,  branching  stems  from  6  inches 
to  2  feet  in  height.  Leaves  all  submerged,  linear,  obtuse  and 
mucronate  or  acute  at  the  apex,  i-3-nerved,  biglandular  at  base, 
rarely  glandless,  1-3  inches  long  and  ^-^  line  broad.  The  typ- 
ical form  (var.  vulgaris.  Fries.  Nov.  p.  49),  has  leaves  3-nerved, 
from  a  little  less  than  ^  to  ^  line  broad,  obtuse  or  shortly  acute, 
and  not  unfrequently  cellular-reticulate  between  the  midrib  and 
the  lateral  nerves.  The  leaves  are  sometimes  revolute  and  slightly 
ridged  in  the  middle,  resembling  in  this  respect  those  of  P.  rutilus. 
Another  common  form  has  the  leaves  about  ^  line  wide,  almost 
setaceous,  i-3-nerved,  the  lateral  nerves  obscure  or  obsolete,  acute 
(var.  tenutssimtfs,  M.  and  K.  Deut.  Fl.  i.  857.  P.  gracilis,  Fries, 
Nov.  p.  50). 

Both  of  these  forms  are  occasionally  provided  with  reproduc- 
tive buds. 

Stipules  short,  hyaline,  obtuse,  when  enclosing  the  bud  boat- 
shaped.  Peduncles  vary  greatly  in  length,  generally  from  3  to  9 
lines  long,  but  occasionally  elongated  from  I  to  3  inches,  and 
sometimes  thickened '  in  fruit.  Spikes  about  as  often  interrupted 
as  capitate  in  all  the  forms,  3-io-flowered.  Fruit  obliquely  ellip- 
tical, 2^-1  line  long  and  ^-^  line  wide,  curved  and  2-grooved 
on  the  back,  or  sometimes  with  3  distinct  keels;  face  slightly 
arched  or  often  with  a  projecting  curve  above  and  an  inward  curve 
below,  beaked  by  a  short,  straight  or  recurved  style ;  apex  of  the 
embryo  slightly  incurved  and  pointing  obliquely  downwards. 


46 

Var.  PANORMITANUS  (Biv).  Morong. 

P.  Panormitanits,  Biv.  Sic.  PI.  (1806-7). 

Uppermost  leaves  subcoriaceous,  spatulate,  opposite,  divaricate, 
in  i  or  2  pairs,  3-5 -nerved,  with  cross-veins  and  often  covered 
with  a  chain-like  areolation,  4-5  lines  long,  sloping  at  base  into  a 
broad  petiole  as  long  as  the  blade.  Collected  in  pools  at  Ottawa, 
Canada,  by  James  Fletcher,  July  1882. 
Var.  POLYPHYLLUS,  Morong,  Bot.  Gaz.  v.  51  (1880). 

A  dwarf  form  3-5  inches  high,  divaricately  branching  from  the 
base,  and  very  leafy  throughout.  Leaves  very  obtuse,  3-nerved. 
Not  flowering,  but  abundantly  provided  with  propagating  buds 
which  are  found  on  the  thickened  and  hardened  ends  of  the 
branches,  and  closely  invested  by  imbricated  leaves.  In  a  shallow 
pool,  with  oozy  bottom,  some  distance  underwater,  South  Natick, 
Mass.  (Morong);  Fresh  Pond,  Cambridge,  Mass.  (Faxon). 
Var.  ELONGATUS,  Ar.  Bennett.  Macoun's  Cat.  Can.  PI.  Pt.  5,  371 

(1890). 

I  have  not  seen  a  specimen  of  this  form,  but  it  is  thus  de- 
scribed by  Mr.  Bennett  in  Jour.  Bot.  for  May,  1891,  p.  151: 
"  This  differs  from  pusillus  by  the  larger  size  of  all  its  parts  and  very 
long  internodes;  leaves  remarkably  elongated ;  peduncles  stout  and 
long ;  spikes  much  longer ;  leaves  often  quite  acute  ;  flowers  larger 
in  all  their  parts.  Habit  of  rutilus,  Wolfg.,  and  so  named  in  speci- 
mens from  Hungary  in  Herb.  Mus.  Brit."  Coll.  Macoun,  Spallum- 
sheen  River,  at  and  above  Enderby,  B.  C. 

Var.  STURROCKII,  Ar.  Bennett,  in  Hook.  Stud.  Fl.  435  (1884). 

This  form  occurs  rather  rarely  in  the  United  States.  It  is  dis- 
tinguished by  its  delicate,  bright  green,  pellucid  leaves,  which  are 
1-3  inches  long,  obtuse  or  often  apiculate  at  the  apex  and  ^-^ 
line  broad.  Mr.  Bennett  states  that  the  British  specimens  are 
sometimes  5 -nerved,  but  I  have  seen  none  with  more  than  3 
nerves.  There  is  often,  however,  at  least  in  American  specimens, 
a  finely-reticulated  space  on  each  side  of  the  midrib.  The  fruit, 
according  to  Mr.  Bennett,  is  much  smaller  than  in  the  type,  with 
a  short  beak.  This  I  have  not  seen. 

P.  pusillus  seems  to  be  the  central  species  of  a  group,  being 
approached  on  the  one  hand  by  P.  lateralis,  and  on  the  other  by 


47 

gemmipants  and  major,  all  together  forming  a  well-marked  aggre- 
gate. 

A  widely-diffused  species,  common  in  Canada  from  New  Bruns- 
wick to  British  Columbia,  New  England  to  Louisiana  and  Texas, 
west  to  Oregon  and  California.  San  Luis  Potosi,  Mexico,  Schaff- 
ner,  No.  533.  Europe.  Pools  and  ditches.  July,  August. 
(Plate  LIII.) 

30.  POTAMOGETON  GEMMiPARUS   (Robbins)  Morong,  Bot.  Gaz.    v. 

51  (1880). 
P.  pusillus  L.,  var.  ?  gemmiparus,  Robbins  in  A.  Gray,  Man.  Ed. 

5,489(1867). 

Stems  filiform,  branching,  terete,  greatly  varying  in  height, 
rising  from  5  inches  to  4  feet,  according  to  the  depth  of  water  in 
which  it  grows ;  the  internodes  below,  especially  in  deep  water 
forms,  as  much  as  5  inches  in  length.  Leaves  capillary,  sometimes 
not  as  broad  as  the  stem,  often  with  no  perceptible  midrib,  taper- 
ing to  the  finest  point,  1-3  inches  long,  biglandular  at  base; 
stipules  1/^-1  inch  in  length,  acute  or  obtuse,  mostly  deciduous. 
Rarely  flowering,  the  spikes  interrupted,  3-6-flowered ;  peduncles 
filiform,  sometimes  a  little  thickened,  ^-2  inches  long.  Fruit  ex- 
ceedingly rare,  and  in  size  and  shape  like  that  of  P.  pusillus,  except 
that  it  is  flatter  and  somewhat  impressed  on  the  sides.  It  is  com- 
monly propagated  by  gemmae,  which  are  abundant.  The  leaves 
and  stems  are  often  alike  in  thickness,  so  that  the  plant  seems  to 
consist  of  threads,  and  this  with  the  long,  naked  internodes,  ren- 
ders its  appearance  very  peculiar. 

A  few  specimens  in  fruit  were  obtained  at  Amherst,  Mass,  by 
Prof.  H.  G.  Jesup  in  1874,  and  by  him  sent  to  Dr.  Robbins,  who 
thereupon  substituted  in  his  herbarium  the  name  here  adopted.  It 
was  first  found  by  Dr.  Robbins  in  the  Blackstone  Valley  from  Wor- 
cester, Mass,  to  Providence,  R.  I.,  and  has  since  been  collected  by 
myself  in  the  Charles  River,  at  South  Natick,  Mass.  Also  by  Mr. 
J.  F.  Collins,  in  Central  Pond,  R.  I.  Pools  and  slow  moving 
streams.  August,  September.  (Plate  LIV.  The  rare  fruiting 
form  is  seen  on  the  right.) 


48 

31.    POTAMOGETON    DIVERSIFOLIUS,    Raf.    Med.    RepOS.    2d    Hex.    V. 

354(1808). 

P.  hybridus,  MX.  Fl.  i.  101  (1803). 

We  are  obliged  to  drop  the  name  of  Michaux,  because  it  had 
been  previously  employed  by  Thuillier  for  P.  heterophyllus  (Fl.  Par. 
1 790),  and  that  of  Rafinesque  comes  next  in  date. 

Stems  flattened,  sometimes  terete,  much-branched,  but  never 
recurved  as  sometimes  occurs  in  P.  Spirillus.  Floating  leaves 
coriaceous,  the  largest  12  lines  long  by  6  lines  wide,  oval,  ellipti- 
cal and  obtuse  or  lance-oblong  and  acute.  Petioles  generally 
shorter,  but  sometimes  longer  than  the  blades,  filiform  or  dilated. 
Submerged  leaves  setaceous,  flat,  in  the  typical  form  seldom  over 
y^  line  in  width,  1-3  inches  long,  I -nerved,  often  with  many  fine 
lines  and  long  reticulations  on  each  side  of  the  midrib.  Stipules 
obtuse  or  truncate,  hyaline,  3-5  lines  in  length,  on  the  floating  leaves 
free,  on  the  submerged  leaves  commonly  adnate  to  the  petiole,  but 
often  free.  Emersed  peduncles  3-7  lines  long  and  thickened  upwards. 
Submerged  peduncles  2-3  lines  long,  as  long  as  the  spikes,  clavate, 
often  recurved.  Emersed  spikes  3-5  lines  long,  occasionally  inter- 
rupted. Fruit  rarely  over  y2  line  long  and  nearly  as  broad,  3- 
keeled,  middle  keel  narrowly  winged,  usually  with  7  or  8  knob-like 
teeth  on  the  margin,  the  lateral  keels  sharp  or  sometimes  rounded ; 
style  quite  apparent  as  a  short  point,  apical ;  embryo  coiled  i  yz 
times.  This  and  the  following  species  are  much  alike  in  general 
appearance  and  often  confounded.  In  well-marked  forms,  how.- 
ever,  the  two  may  readily  be  distinguished  not  only  by  the  differ- 
ence in  the  submerged  peduncles,  but  by  the  width  of  the 
submerged  leaves,  those  of  P.  diversifolius  being  capillary  or 
setaceous  and  only  i  -nerved.  Sometimes  the  leaves  are  broader, 
and  then  the  chief  mark  of  distinction  lies  in  the  submerged  pe- 
duncles. Both  species  are  really  intermediate  between  the  section 
of  Potamogetons  with  free  stipules  and  that  with  adnate  stipules, 
as  in  the  uppermost  leaves  the  stipules  are  free,  and  adnate  only 
in  the  lower.  In  extent  of  adnation  this  species  approaches  the 
former  and  the  following  species  the  latter. 
Var.  MULTI-DENTICULATUS,  Morong,  n.  var. 

Varies  from  the  type  in  the  numerous  teeth  on  the  fruit,  as 
many  as  12  being  sometimes  found  on  the  middle  keel,  and  each 


49 

lateral  keel  with  6  or  8  more.  Frequently  the  teeth  are  bristle- 
like,  and  sometimes  2-pronged.  The  submerged  leaves  are  from 
]/±  to  y2  line  in  width,  rarely  as  narrow  as  in  the  type.  The  most 
distinctly-marked  specimens  of  this  form  were  collected  by  Mr.  C. 
F.  Parker  in  a  pond  at  Rehoboth  City,  Delaware,  August  7,  1878. 
I  have  since  noted  the  following  localities  for  it :  Noank,  Conn. 
(Morong) ;  ponds  on  the  Susquehanna  land  at  Easton,  Pa.-  (Por- 
ter) ;  Florida  (Curtiss,  Regel,  No.  72) ;  Lower  Louisiana  (Langlois). 
Var.  TRICHOPHYLLUS,  Morong,  n.  var. 

About  6  inches  in  height,  without  floating  leaves,  the  sub- 
merged leaves  as  fine  as  floss  silk,  and  entirely  destitute  of  nerves. 

Coll.  N.  L.  Britton,  Lake  Marcia,  Sussex  Co.  New  Jersey. 

The  species  in  pools  and  ponds  from  New  England  to  Nebraska, 
and  south  to  Florida  and  Texas,  San  Luis  Potosi,  Mexico  (Schaff- 
ner  No.  534  and  Parry  and  Palmer  No.  856).  Cuba  (Wright).  It 
ranges  farther  to  the  south  than  Spirillns  and  not  so  far  north.  It 
occurs  in  Maine,  but  Prof.  Macoun  expresses  a  doubt  whether  the 
Canadian  forms  attributed  to  this  species  are  not  Spirillus  and  such 
as  I  have  seen  from  Canada  confirm  his  opinion.  (Plate  LV.) 

32.  POTAMOGETON  SPIRILLUS,  Tuckerm.  Am.  Jour.  Sci.  and  Arts, 

2d  series,  vi.  228  (1848). 
P.  Zctterstcdtii,  Wallm.  ap.  Sch.  et  Mohl.  Bot.  Zeit.  i.  256  (1843)? 

(fide  Bennett  Jour.  Bot.  xxviii.  298.) 

Stems  compressed,  much  branched,  the  branches  often  short 
and  recurved,  6-20  inches  high.  Floating  leaves  coriaceous,  ob- 
tuse, usually  opposite  and  in  several  pairs  towards  the  summit  of 
the  stem,  oval  or  elliptical,  varying  to  lanceolate,  the  largest  about 
12  lines  long  by  6  lines  wide,  sometimes  narrow-oblong,  deeply 
impressed  beneath  by  5-i3-nerves.  Petiole  commonly  about 
equal  to  the  blade,  but  sometimes  only  ^  or  y2  its  length,  some- 
what dilated.  Submerged  leaves  linear,  obtuse  or  abruptly  acute, 
1^-2  lines  long  and  Y^-^/2  line  wide,  uppermost  sometimes  I  line 
wide,  usually  3-nerved,the  lateral  nerves  near  the  margin,  rarely  with 
5  very  delicate  nerves,  often  with  irregular  reticulated  spaces  on 
each  side  of  the  midrib.  Stipules,  like  those  of  the  preceding 
species,  on  the  uppermost  floating  leaves  entirely  free,  on  the  lower 
adnate  to  the  petiole  near  the  base,  on  the  submerged  adnate  to 


50 

the  leaf  for  about  one-half  their  length.  In  dried  specimens,  the 
stipules  appear  free  from  all  the  floating  leaves.  Emersed  pe- 
duncles usually  similar  to  those  of  the  preceding  species.  Sub- 
merged peduncles  usually  wanting,  or  at  most,  hardly  I  line  long. 
Spikes  above  water  3-5  lines  long,  continuous,  while  the  lower 
are  mostly  sessile  in  the  axis  of  branches,  capitate  aud  ripening 
from  i  to  4  fruit.  Fruit  cochleate,  very  thin,  nearly  fleshless, 
roundish,  about  $£  line  long  and  nearly  as  broad,  flat  and  deeply 
impressed  on  the  sides,  3-keeled  on  the  back,  middle  keel  winged, 
wing  broad  and  with  4  or  5  large  teeth  or  very  narrow  and  with- 
out teeth,  the  lateral  keels  rounded ;  style  usually  marked  on  the 
dried  fruit  only  by  a  slight  projection  or  a  scar ;  embryo  commonly 
coiled  about  I  ^  turns.  The  spiral  markings  of  the  embryo  are 
distinctly  seen  in  the  dried  fruit,  and  are  a  very  distinctive  feature, 
strongly  reminding  one  of  a  small  snail  shell. 

Pools,  ditches  and  ponds.  Nova  Scotia  (Mrs.  E.  G.  Britton) ; 
New  Brunswick,  Quebec  and  Ontario  (Macoun).  Common  in 
New  England,  and  west  to  Minnesota,  Missouri  (Blankenship) 
and  Nebraska,  south  to  Pennsylvania  and  Virginia.  (Plate  LVI.) 
33.  POTAMOGETON  FiLiFORMis,  Pers.  Syn.  i.  152  (i8os). 
P.  marinus  of  authors,  not  L.  Herb. 

Stems  from  a  running  rootstock,  slender,  3-20  feet  in  height, 
filiform  above,  stout  and  thick  towards  the  base.  Flowers  on 
long,  often  drooping  peduncles,  the  longest  measuring  6  to  8 
inches,  2-4  in  a  whorl  and  the  whorls  ]^-i  inch  apart.  Leaves 
numerous,  2-10  inches  long  and  from  ^  to  ^  line,  very  rarely  ^ 
line,  broad,  i -nerved,  with  a  few  cross  nerves.  Sheaths  about  i 
line  long,  and  the  free  part  of  the  stipule  */2  inch  more,  scarious  on 
the  edges.  From  3  to  12  drupes  are  ripened  in  a  verticil.  Fruit 
\-il/2  lines  long  and  about  ^  line  wide;  sides  even  ;  back  not 
keeled  in  fresh  specimens  and  scarcely  so  in  the  dry ;  face  nearly 
straight  or  obtusely  angled  near  the  top ;  stigma  nearly  or  quite 
sessile,  remaining  on  the  dry  fruit  as  a  broad  truncate  projection, 
apical  or  subapical ;  embryo  circle  incomplete,  the  apex  pointing 
slightly  inside  of  the  basal  end. 

Var.  MACOUNII,  Morong,  Macoun's  Cat.  Can.  PL  pt.  4.  88  (1888.) 

Quite  a  distinct  form  with  leaves  1-3  inches  long,  the  largest 

l/2  a  line  or  a  little  more  in  width,  obtuse,  stiff,  with  a  strong  mid- 


51 

rib  and  raised  or  slightly  revolute  margins.  Fruit  small,  rarely 
more  than  a  line  in  length  and  ^  of  a  line  in  breadth.  Peduncles 
short,  not  more  than  8  or  10  lines  long  at  the  most.  This  form 
commonly  has  a  compact,  bushy  habit  which  is  quite  noticeable. 
Occurs  in  brackish  and  salt  lakes  of  the  prairie  region,  in  Old 
Wives'  Lakes  and  Crawling  Valley,  south  of  the  Hand  Hills, 
Alberta,  Canada  (Macoun).  This  approaches  : 
Var.  occidentalis,  Robbins,  Bot.  King's  Ex.  339  (1871). 

This  as  described  by  Robbins  has  some  of  the  leaves  similar  to 
those  of  the  preceding  variety,  but  the  peduncles  often  as  much 
as  6  inches  long,  the  fruit  roundish-obovate,  and  the  sides  of  the 
nutlet  made  "  uneven  by  a  central  elevation  partially  surrounded 
by  a  shallow  depression  which  is  marginned  by  the  raised  lateral 
keel."  Ruby  Lake,  Nevada,  6,000  feet  alt.,  (Watson);  Shoshone 
Geyer  Basin,  Wyoming  (Clifford  Richardson). 

The  species  is  rare  in  the  United  States,  and  was  first  detected 
by  myself  in  the  rapids  above  Niagara  Falls  in  1875,  and  since  in 
similar  rapids  at  Sault  Ste.  Marie,  Mich.  It  is  abundant  in  Seneca 
Lake,  N.  Y.,  and  Mr.  Hill  has  obtained  it  in  Hemlock  Lake, 
Western  New  York  and  Frankfort,  Mich.  It  is  more  common  in 
Canada,  having  been  obtained  by  Prof.  Macoun  in  brackish  marshes 
on  the  sea  coast  at  the  Island  of  Anticosti,  and  in  fresh  water  lakes 
and  creeks  in  the  Northeast  territory,  Manitoba  and  British  Colum- 
bia. August.  (Plate  LVII.) 

34-    POTAMOGETON  PECTINATUS,  L.  Sp.  PI.   127  (17S3}- 

Stems  slender,  from  a  running  rootstock,  much  branched,  the 
branches  repeatedly  forking,  I  to  3  feet  in  height,  usually  much 
stouter  below.  Leaves  setaceous,  attenuate  to  the  apex,  I -nerved, 
1-6  inches  long,  often  capillary  and  without  nerves.  Gigantic 
forms  were  collected  by  Prof.  W.  R.  Dudley  in  Lake  Cayuga,  from 
1 8  to  20  feet  in  length,  and  with  leaves  even  10  inches  long.  The 
form  scoparius,  Wallr.,  found  in  this  country  as  well  as  in  England, 
has  numerous  hair-like  fasciculated  leaves,  very  long  and  broom- 
like  in  appearance,  whence  the  name.  Stipules  with  sheaths 
which  are  white  and  scarious  on  the  edges,  */£-!  inch 
long,  and  half  as  much  free.  Peduncles  filiform,  2  to  12  inches 
long,  the  flowers  in  approximate  or  distant  verticils,  2  to  4  flowers 


52 

ripening  2  to  8  seeds,  in  a  verticil.  Fruit  roundish  obovate  or 
obliquely  obovate,  with  a  thick  hard  shell,  I  y&-2  lines  long  and 
i-i  y±  lines  wide,  without  a  middle  keel,  but  with  obscure  lateral 
ridges  on  the  back,  plump  on  the  sides,  and  curved,  occasionally 
a  little  angled  on  the  face;  style  distinct,  straight  or  recurved, 
facial ;  embryo  apex  nearly  touching  and  pointing  directly  towards 
the  basal  end.  In  American  plants,  the  keels  are  generally  ob- 
scure and  often  obsolete,  and  the  fruit  more  nearly  approaches 
that  oi  filifonnis  in  size. 

This  species  is  frequently  propagated  by  root  tubercles  which 
are  nearly  as  large  as  peas  and  lie  imbedded  in  the  mud  through 
the  winter.  In  this  state  they  are  eaten  by  wild  fowl,  and  the 
crops  of  these  birds  are  often  filled  with  them. 

P.  pectinatus  and  P.  filifonnis  are  often  confounded,  and  in 
the  absence  of  fruit  it  is  impossible  in  all  cases  to  make  sure  of 
the  species.  As  a  general  rule  P.  filifonnis  is  a  smaller  plant. 
In  regard  to  the  fruit,  that  of  P.  pectinatus  may  always  be  known 
from  filifonnis  by  its  distinct  and  often  recurved  style,  and  usually 
it  is  larger.  Both  species  occur  in  brackish  water,  sometimes  in 
tidal  and  salt  wrater,  and  also  veiy  extensively  in  fresh  water. 

Ponds  and  rivers.  Widely  distributed  in  Canada  from  Cape 
Breton  to  British  Columbia  and  northwards  (Macoun).  In  the 
United  States  it  ranges  from  New  England  to  Florida  and  Texas,  and 
across  the  continent  to  Oregon  and  California.  Lower  California 
(Orcutt,  Palmer).  Southern  Mexico  (Helmsley).  Cuba  (Wright). 
A  world-wide  species,  occurring  in  Europe,  Australia,  Africa  and 
Asia.  (Plate  LVIII.) 

35.  POTAMOGETON  LATiFOLius  (Robbins)  Morong. 

P.  pectinatus,  var.  (?)  latifolius,  Robbins,  Bot.  King's    Ex.    338 

(1871). 

Stem  stout,  white,  branching,  2-3  feet  high.  Leaves  numer- 
ous, flat,  1-3  inches  long  and  1-2  lines  broad,  3-5  nerved,  reticu- 
late with  many  cross  veins,  obtuse  or  abruptly  apiculate,  the  nar- 
rower ones  acute.  The  part  of  the  stipule  adnate  to  the  leaf,  broad, 
many-nerved,  scarious-margined,  y2-\  inch  long,  the  free  portion 
shorter.  Peduncles  1-3  inches  long.  Spikes  interrupted.  Mature 
fruit  much  like  those  of  pectinatus,  while  the  foliage  differs  greatly. 


53 

Fruit  about  2  lines  long  by  \y2  lines  wide;  back  usually  without 
a  keel,  the  lateral  ridges  rounded;  face  gibbous  at  the  top;  style 
facial,  rather  long,  erect  or  slightly  recurved;  embryo  apex  point- 
ing slightly  inside  of  the  basal  end.  Often  in  the  fruit  the  curve 
of  the  back  rises  at  the  top  almost  as  high  as  the  style,  making 
that  appear  as  if  on  the  face,  a  peculiarity  which  occurs  sometimes 
in  pcctinatns  also.  It  is  a  question  whether  this  form  is  the  same 
as  the  broad-leaved  forms  of  flabcllatus,  but  it  differs  from  that 
species  not  only  in  fruit  characters,  but  in  having  many  short 
lateral  branches,  shorter  and  more  obtuse  leaves,  and  a  stouter 
and  stricter  stem. 

The  plant  described  by  Robbins  was  collected  in  the  "running 
brackish  waters  of  Humboldt  River  below  Humboldt  Lake,"  Ne- 
vada. A  fine  specimen  is  in  the  Herb,  of  Mr.  I.  C.  Martindale,  of 
Camden,  New  Jersey,  collected  by  Mrs.  R.  M.  Austin  in  Goose 
Lake,  Northeastern  California,  in  Sept.  1884.  The  fruit  here  de- 
scribed is  taken  from  that  specimen.  (Plate  LIX.) 

36.  POTAMOGETON  INTERRUPTUS,  Kitaibel;  Schultes,  CEst.  Fl.  Ed. 

2,  328  (1814),  fide  Ar.  Bennett. 
P.flabdlatus,  Babington,  Man.  Bot.  Ed.  3,  343  (1851). 

From  a  running  rootstock  which  often  springs  from  a  small 
tuber.  Stems  stout,  branching,  2-3  feet  in  height,  the  branches 
spreading  like  a  fan.  Leaves  linear,  obtuse  or  acute,  3-5  inches 
long,  i  line  or  a  little  more  in  width,  3-5 -nerved,  with  many  trans- 
verse veins.*  Narrow,  I -nerved  leaves  occur  on  some  plants,  and 
these  are  acuminate,  much  like  those  of  P.  pectinatus.  Stipule  on 
the  adnate  part  ^-i  inch  long,  without  scarious  edges,  or  nar- 
rowly scarious,  the  free  part  shorter  and  scarious,  obtuse.  Pe- 
duncles 1-2  inches  long.  Spikes  slightly  interrupted. 

Our  United  States  plants  have  never  been  observed  in  fruit, 
but  I  am  able  to  give  the  fruit  characters  from  specimens  kindly 

*It  should  be  noted  that  Mr.  Fryer  regards  these  broad  leaves  as  belonging  mostly 
to  sterile  or  autumnal  shoots.  Normally,  as  he  describes  the  leaves,  they  are  narrow 
or  setaceous  like  those  of  pectinatus.  The  chief  difference  between  the  species  and 
pectinatus,  in  his  opinion,  lies  in  the  fruit.  But  as  these  broad  leaves  are  the  only 
ones  so  far  found  in  the  United  States,  and  as  they  are  the  kind  originally  attributed  to 
the  species  by  Prof.  Babington,  I  can  only  pay  regard  to  their  in  this  account  of  our 
species. 


54 

furnished  by  Mr.  Fryer  and  collected  by  him  in  Cambridgeshire, 
England,  where  the  plant  is  common.  Fruit  broadly  obliquely 
obovate,  obtuse  at  base,  the  largest  2  lines  long  by  i^  lines  wide, 
prominently  keeled  and  with  rounded  lateral  ridges  on  the  back ; 
face  nearly  or  quite  straight,  sometimes  gibbous  at  the  top ;  style 
facial,  erect;  embryo  outline  obovate,  the  apex  pointing  slightly 
inside  of  the  basal  end.  The  shell  of  the  drupe  is  exceedingly 
thick  and  quite  hard. 

First  found  by  Mr.  E.  J.  Hill  in  ponds  at  Manistee,  Mich.,  and 
subsequently  collected  by  myself  in  the  same  locality.  Also  col- 
lected by  Mr.  Hill  in  the  Channel  Islands,  St.  Mary's  River,  Mich. 
Mr.  Hill  takes  especial  notice  of  the  tubers  by  which  this  species 
is  frequently  propagated.  This  method  of  propagation  it  has  in 
common  with  P.  pectinatus,  to  which  it  is  closely  allied.  (Plate 
LX.) 

37.  POTAMOGETON  RoBBiNsn,  Oakes,   Hovey's  Mag.  May,   1841, 

p.  2. 

Stems  stout,  widely  branching,  2-4  feet  high,  from  running 
rootstocks  sometimes  10  or  12  inches  long.  Leaves  3-5  inches 
long,  2-3  lines  wide,  acute,  finely  many-nerved,  crowded  in  2 
ranks,  minutely  serrulate  under  the  lens,  auriculate  at  the  point  of 
attachment  with  the  stipule.  Stipules  with  the  adnate  portion  and 
sheathing  base  of  the  leaf  about  y2  an  inch  long,  the  free  part  from 
y2  to  I  inch,  acute,  persistent,  white,  membranous,  mostly  lacerate. 
Peduncles  1-3  inches  long,  the  infloresence  frequently  much 
branched  and  bearing  from  5  to  20  peduncles.  Spikes  interrupted, 
^-^  inch  long,  flowering  under  water,  but  the  rarest  of  all  our 
North  American  species  to  form  fruit.  It  is  propagated  very  ex- 
tensively by  fragments  of  the  stems,  which  throw  out  many  root- 
lets from  every  joint.  I  have  seen  such  rootlets  from  6  to  10 
inches  long  on  floating  specimens,  and  even  a  stem  standing  up- 
side down  in  the  mud  and  growing  apparently  as  well  as  in  the 
normal  position.  Very  rarely  in  years  when  the  waters  are  low, 
the  flowering  spikes  rise  above  the  surface  and  perfect  a  few  fruit. 
Dr.  Robbins  never  saw  but  one  fruit,  which  was  collected  many 
years  ago  in  Oregon  by  Hall,  and  this  was  split  in  two,  Prof.  D.  C. 
Eaton  taking  one-half  and  Dr.  Robbins  the  other.  In  the  year 


55 

1 880  Mr.  E.  Faxon  had  the  good  fortune  to  secure  a  few  fruiting 
specimens  in  Jamaica  Pond,  Mass.  Besides  them  I  have  never 
known  another  instance,  although  the  plant  is  very  prolific  in  the 
localities  where  it  occurs,  sometimes  densely  covering  the  bottoms 
of  ponds  for  acres.  Mature  fruit  obovate,  about  2  lines  long  by 
I  y2  lines  wide,  3-keeled  on  the  back,  the  middle  keel  sharp  and 
prominent,  the  laterals  rounded  ;  face  arched  ;  sides  with  a  shallow 
depression  which  runs  into  the  face  below  the  arch ;  style  sub- 
apical,  thick,  slightly  recurved,  obliquely  truncate;  apex  of  the 
embryo  pointing  slightly  inside  of  the  basal  end. 

So  far  as  known,  confined  to  the  northern  part  of  North 
America.  New  Brunswick,  Ontario,  Lake  Superior  (Macoun) ; 
New  England  to  Northern  New  Jersey,  and  westward  to  Oregon 
(Hall,  Wilkes'  Exploring  Expedition).  (Plate  LXI.) 

5.  RUPPIA,  L.  Sp.  PI.  127  (1753). 

Stems  capillary,  widely  branched.  Leaves  very  slender,  alter- 
nate, I -nerved,  tapering  to  an  acuminate  point,  with  a  membranous 
sheath  at  the  base.  Flowers  on  a  capillary,  spadix-like  peduncle, 
naked,  perfect,  consisting  of  two  sessile  anthers,  each  with  2  large, 
separate  cells,  attached  by  the  back  to  the  peduncle,  having  be- 
tween them  several  pistillate  flowers,  in  2  sets,  on  opposite  sides 
of  the  rachis,  the  whole  at  first  enclosed  in  the  sheathing  base  of 
the  leaf;  stigmas  sessile,  peltate.  In  the  development,  the  stami- 
nate  flowers  drop  off,  and  the  peduncle  elongates,  bearing  the 
pistillate  flowers  in  two  clusters  at  the  end.  The  flowers  are  ferti- 
lized above  water,  after  which  the  peduncles  coil  up  and  are  drawn 
beneath  the  surface.  Fruit  a  small,  obliquely  pointed  drupe,  several 
in  each  cluster,  pedicelled ;  embryo  oval,  the  cotyledonary  end  in- 
flexed,  and  both  that  and  the  radicle  immersed. 

Half  a  dozen  or  more  species  have  been  enumerated,  but  prob- 
ably all  may  be  reduced  to  two  or  three.  In  salt,  brackish  and 
fresh  waters  throughout  the  world. 

i.  RUPPIA  MARITIMA,  L.  Sp.  PI.  127  (1753). 

Stems  often  whitish,  2  or  3  feet  high,  the  nodes  irregular, 
naked,  1-3  inches  long.  Leaves  1-3  inches  in  length  and  ^  line  or 
less  in  breadth  ;  sheaths  membranous,  3-4  lines  long  and  with  a 
minute  ligule  or  short  free  tip  at  the  top.  In  fruit  the  peduncles 


56 

are  greatly  elongated,  sometimes  as  much  as  1 2  inches  or  even 
more  ;  pedicels  4-6  in  a  cluster,  y2-il/2  inches  in  length.  Drupes 
with  a  dark  hard  shell,  about  I  line  long,  ovoid,  often  oblique  or 
gibbous  at  base,  pointed  with  the  long  style.  The  drupes  vary  a 
good  deal  in  shape,  usually  simply  conical  with  a  short  gibbous 
swelling  at  the  base,  sometimes  with  a  strong  spur-like  projection 
and  a  curved  outline,  as  in  the  form  known  in  Europe  as  R.  ros- 
tellata,  Koch,  which  does  not,  however,  differ  otherwise  from  the 
type.  Specimens  with  fruit  of  this  shape  are  sent  from  Oregon 
by  Mr.  Howell.  Forms  with  fruit  nearly  destitute  of  peduncles 
and  pedicels,  and  broad  strongly  marked  sheaths,  similar  in  these 
respects  to  R.  bracliypiis,  Gay,  occur  at  Wood's  Roll,  Mass.,  and 
at  other  places  along  the  Atlantic  coast.  (Plate  LXII.) 

2.  RUPPIA  OCCIDENTALIS,  S.  Watson,  Proc.  Am.  Acad.  Sept.  25, 

1890,  p.  138. 
R.  lacnstris,  Macoun,  Cat.  Can.  PL  Pt.  5.  372,  Nov.  1890. 

A  stoutish-stemmed  plant  1-2  feet  high,  the  branches  forking 
in  fan  shape.  Leaves  3-8  inches  long,  with  large  sheaths  ^-i^ 
inches  in  length.  Branches  and  leaves  often  thickly  clustered  at 
the  nodes,  the  sheaths  overlapping  each  other.  Drupes  large, 
I  y2-2  lines  long,  of  a  thick  pear  shape,  on  pedicels  ^-i  inch  long. 
Prof.  Macoun  states  that  the  peduncles  are  bright  red  when  fresh. 

Coll.  by  Macoun  in  a  saline  pond  at  Kamloops,  B.  Columbia. 
Also  collected  by  H.  J.  Webber  in  a  saline  region  at  Alliance, 
Box  Butte  Co.,  Nebraska.  Mr.  Webber  writes  that  he  found  pe- 
duncles nearly  2  feet  in  length.  (Plate  LXII  I.) 

6.  ZANNICHELLIA,  L.  Sp.  PL  969  (1753). 
Stems,  flowers  and  leaf  buds  all  at  first  enclosed  in  a 
hyaline  envelope,  a  sort  of  spathe,  corresponding  to  the  stipule  of 
Potawcgoton,  rising  from  a  node.  Staminate  and  pistillate  flowers 
in  the  same  axil ;  the  stamen  solitary,  2-celled,  on  a  short  pedicel- 
like  filament ;  pistillate  2-5  or  more  in  a  special  envelope  of  their 
own.  The  stamen  is  said  to  be  4-celled  occasionally,  but  I  never 
could  find  more  than  2  cells.  Ovary  a  flask-shaped  body,  stipulate 
at  base,  tapering  into  a  short  style,  with  a  broad,  hyaline  stigma 
which  is  somewhat  cup-shaped,  and  has  irregular,  angled  or  den- 
tate edges.  Sometimes  the  whole  cluster  of  flowers  is  on  a  stipe 


57 

or  peduncle.  In  fruit  the  stipe  and  style  lengthen,  and  the  ovary 
is  prolonged  iuto  a  flattish,  falcate  nutlet,  ribbed  or  sometimes 
toothed  on  the  back.  Seeds  corresponding  to  fruit ;  the  embryo 
bent  and  coiled  at  the  cotyledonary  end. 

Found  in  all  parts  of  the  world.  Haifa  dozen  different  species 
have  been  described  by  authors,  but  most  of  them  can  be  reduced 
to  the  following  species,  and  probably  not  more  than  2  or  3  species 
exist. 

i.  ZANNICHELLIA  PALUSTRIS  L,  Sp.  PI.  969  (1753). 

Flowering  and  ripening  its  fruit  under  water.  Stems  capillary, 
sparsely  branched,  from  a  creeping  rhizome  and  fibrous  roots,  1-2 
feet  high.  Leaves  1-3  inches  long,  */£  line  or  less  in  breadth, 
acute,  thin,  I -nerved  and  with  a  few  delicate  cross  nerves.  Spathe 
or  stipule  separating  from  the  leaves  and  fruit  at  maturity,  per- 
sistent. Fruit  2-4,  sometimes  6,  in  a  cluster,  falcate,  1-2  lines 
long,  variously  disposed,  sometimes  sessile,  sometimes,  as  in  forma 
pediccllata,  J.  Gay,  each  on  a  pedicel,  or,  as  in  forma  pedunculata 
A.  Gray,  the  whole  cluster  on  a  short  peduncle.  The  fruit  is  gen- 
erally ribbed  or  winged  on  both  margins,  but  sometimes  without 
an  apparent  rib  and  sometimes  dorsally  knobbed  or  toothed ;  style 
persistent,  recurved,  J^-i  line  long.  In  var.  muricata,  Morong, 
which  occurs  in  Texas  and  California,  the  fruit  has  distinct  teeth 
on  the  back  and  is  bristly-muricate  on  the  sides.  All  these  forms 
may  sometimes  be  found  on  a  single  plant,  or,  at  least,  in  the  same 
cluster,  and  can  hardly  be  regarded  as  varieties. 

Fresh  and  brackish  ponds  and  pools,  sometimes  in  tidewater. 
Common  throughout  Canada  and  the  United  States,  as  well  as  in 
all  other  parts  of  the  world.  (Plate  LXIV.) 

7.  NAIAS.  L.  Sp.  PI.  1015  (1753). 

Slender,  branching  plants  with  fibrous  roots,  wholly  submerged. 
Leaves  opposite,  alternate  or  verticillate  in  3's  or  more,  sheathing 
at  the  base,  nerveless.  Flowers  monoecious  or  dioecious,  axillary, 
solitary,  sessile  or  pedicellate.  Sterile  flower  with  a  double  peri- 
anth, the  exterior  one  entire  or  4-horned  at  the  apex,  the  internal 
hyaline,  adhering  to  the  anther;  stamen  sessile  or  stipitate,  1-4- 
celled,  apiculate  or  2-lobed  at  the  apex,  rupturing  irregularly. 
Fertile  flower  of  a  single  ovary  which  tapers  into  a  short  style 


58 

that  is  split  somewhat  irregularly  into  2-4  subulate  stigmas.  The 
mature  carpel  is  solitary,  sessile,  ellipsoidal,  with  a  crustaceous 
pericarp;  seed  conformed  to  the  pericarp,  and  the  embryo  to  the 
seed,  the  plumule  and  radicle  immersed.  Generally  the  raphe  is 
distinctly  marked  on  the  seed. 

About  10  species  are  known,  inhabitants  of  fresh  water  in 
tropical  and  temperate  regions.  Four  species  occur  in  North 
America,  three  of  them  belonging  to  the  section  Caulinia,  as  con- 
stituted by  Willdenow,  that  is,  species  with  the  stems  and  backs 
of  the  leaves  unarmed. 

i.  NAIAS  MARINA,  L.  Sp.  PL  1015  (1753). 
N.  major,  All.  Fl.  Fed.  ii.  221  (1785). 

A  dioecious  plant  with  rather  stout  compressed  stems  com- 
monly armed  with  teeth  half  as  long  as  their  breadth.  Leaves  op- 
posite or  in  3's,  6-18  lines  long,  about  I  line  broad,  with  6-io 
spine-pointed  teeth  on  each  margin,  and  frequently  several  along 
the  back.  Sheaths  with  rounded  lateral  edges,  the  type  form 
without  teeth.  The  teeth  vary  much  in  size  and  number.  Some- 
times the  stem  is  entirely  naked,  sometimes  with  only  one  or  two 
teeth.  The  teeth  on  the  leaf  margins  have  a  large  basal  prominence 
which  often  imparts  a  zig-zag  appearance  to  the  outline,  this 
prominence  being  composed  of  several  cells  which  buttress  the 
yellow,  I -celled  spine  at  the  tip.  Fruit  large  (2-2^2  lines  long), 
the  pericarp,  as  well  as  the  seed,  rugosely  reticulate,  tipped  with 
a  long,  persistent  style  and  3  thread-like  stigmas ;  seed  not  shin- 
ing. A  polymorphous  species,  the  extreme  forms  of  which  would 
hardly  be  recognized  as  belonging  together.  A.  Braun  enum- 
erates 6  forms,  of  which  his  variety  Ehrcnbergii,  with  unarmed  stem, 
the  edges  of  the  sheath  furnished  with  1-2  teeth,  occurs  in  Florida 
(Dr.  E.  Palmer);  and  his  variety  intermedia,  or  very  nearly  that,  with 
long,  naked  internodes,  leaves  narrow,  linear,  each  margin  with  5 
or  6  large  teeth,  which  are  usually  longer  than  the  breadth  of  the 
leaf,  without  dorsal  teeth,  the  sheath  on  each  side  with  1-4  teeth, 
and  fruit  nearly  3  lines  long,  occurs  in  Lake  Cayuga,  New  York 
(Morong). 

Besides  these  the  two  following  well-marked  forms  occur  in  the 
United  States : 


59 

Var.  GRACILIS,  Morong,  Bot.  Gaz.  10,  255  (1885). 

Internodes  1-3  inches  in  length,  with  a  few  teeth  near  the 
upper  part.  Leaves  scarcely  ^  line  wide,  with  15  to  24  large 
teeth  on  the  margins  and  few  dorsal  teeth  ;  sheaths  with  2-3  teeth 
on  each  margin  ;  seeds  hardly  2  lines  long  and  sculptured  with 
about  25  rows  of  nearly  square  or  irregularly  oblong  reticulations. 
The  whole  plant,  at  least  when  dry,  purple  tinged. 

Florida  (A.  H.  Curtiss,  No.  2705).     A  form  very  nearly,  if  not 
quite  this,  was  collected  by  Prof.  Wm.  R.   Dudley  off  Canoga 
marshes,  New  York  (Cayuga  Flora,  p.  104). 
Var.  RECURVATA,  Dudley,  Cay.  Fl.  104  (1886). 

Stems  dichotomously  branched,  the  branches  and  leaves  re- 
curved. Leaves  3-6  lines  long,  narrow,  with  2-4  large  teeth  on 
each  margin  longer  than  their  breadth,  without  dorsal  teeth  ;  inter- 
nodes  short,  naked,  or  with  I  or  2  teeth;  sheaths  I -toothed  on 
each  side. 

Black  Lake,  Cayuga  Marshes,  New  York  (Dudley). 

The  species  rare  in  North  America.  Canoga  Marshes  and 
Cayuga  Lake,  N.  Y.  (Morong,  Dudley) ;  Florida  (Chap.  Fl.) ; 
Utah  (Parry) ;  Lower  California  (Palmer.)  Attributed  by  Watson 
in  Bot.  Cal.  to  Clear  Lake  (Bolander)  and  Huntington  Valley, 
Nevada  (Wheeler).  Cuba.  Occurs  in  Europe  and  Asia.  (Plate 
LXV.) 

2.    NAIAS  FLEXILIS  (Willd.)   Rostk.  and  Schmidt.   Fl.  Sed.   384 

(1824). 

Cauliniaflcxilis,  Willd,  in  Act.  Ac.  Berol.  89  (1798). 
Naias  Canadensis,  MX.  Fl.  ii.  220  (1803). 

Stems  slender,  dichotomously  much  branched.  Leaves  linear, 
pellucid,  acuminate  or  abruptly  acute,  */£-!  inch  long  by  y^-\  line 
wide,  numerous  and  crowded  on  the  upper  part  of  the  branches, 
with  25-30  minute  I -celled  teeth  on  each  edge;  sheaths  obliquely 
rounded,  with  5-10  teeth  on  each  edge.  Dioecious.  Fruit  ellip- 
soidal, with  very  thin  pericarp,  i-i  ^  lines  long  and  ^-/^  of  a  line 
in  diameter;  style  long,  divided  into  3  short  stigmas,  persistent ; 
seeds  smooth,  shining,  sculptured,  sometimes  quite  faintly,  with 
30-40  rows  of  squarish  or  hexagonal  reticulations  which  are 
scarcely  seen  through  the  pericarp.  The  seeds  are  generally 


60 

straw  colored,  but  sometimes  quite  dark;  pericarp  dull  and  dark. 
This  species  occurs  in  various  forms,  some  of  them  very  small  and 
bushy,  2  or  3  inches  high,  others  a  foot  or  more  high,  and  nearly 
capillary,  the  foliage  generally  a  dusky  purple,  but  sometimes  a 
bright  green. 
Var.  ROBUSTA,  Morong,  Bot.  Gaz.  x.  255  (1885). 

Stem  stout,  comparatively  few  leaved,  internodes  long,  sparsely 
branched,  3-6  feet  high. 

Ponds  and  rivers  in  Eastern  Massachusetts,  New  York,  Michi- 
gan and  Texas. 

The  typical  plant  is  widely  diffused  in  North  America,  being 
found  in  Canada,  from  the  Atlantic  to  the  Pacific,  and  equally 
common  in  the  United  States  and  Mexico.  It  is  as  widely  dis- 
tributed in  the  Old  World.  (Plate  LXVI.) 

3.  NAIAS  GUADALUPENSIS  (Spreng.)  Morong. 

Caulinia  Gnadalupcnsis,  Spreng.  Syst.  i.  20  (1826). 

N.  flexilis,  var.  (  ?  )  fusiformis,  Chap.  Fl.  /^/|/|  (1860). 

N.  flexilis,  var.  Giiadalupcnsis,  A.  Br.  Seeman's  Jour.  Bot.  ii.  274 

(1864). 
N.  inicrodon,  var.  Gnadalupensis,  A.  Br.  Rep.  Nat.  His.  Soc.  Berl. 

June  1 6,  1868. 
,Y.  uiicrodon,  Morong, 'Bot.  Gaz.  x.  255  (1885). 

Stems  almost  capillary,  1-2  feet  high,  numerously  and  widely 
branched  from  the  base.  Leaves  numerous,  /^-^  of  an  inch  long, 
/^-/^  of  a  line  broad,  acute,  opposite  or  3-5  fascicled,  frequently 
recurved,  with  sheaths  and  teeth  like  those  of  N.  flexilis,  but  gen- 
erally with  40-50  teeth  on  each  edge  of  the  leaf.  Fruit  about  I 
line  long;  pericarp  dark  and  strongly  marked  by  16-20  rows  of 
hexagonal  or  rectangular  reticulations  which  are  transversely  ob- 
long; seed  straw-colored,  not  shining. 

This  species  is  easily  confounded  with  N.  flexilis,  but  is  clearly 
distinct  in  its  long  narrowly  outlined  branches,  its  short  leaves, 
and  especially  in  the  markings  of  the  fruit  and  seed. 

Florida  (A.  H.  Curtiss,  Chapman);  Louisiana  (Langlois);  Texas 
(Lindheimer,  Reverchon);  Nebraska  (T.  A.  Williams);  Oregon 
(Howell).  West  India  Islands  (Duchassaing,  Wright).  Mexico 
(Muller)'.  (Plate  LXVII.) 


61 

4-  NAIAS  GRACILLIMA  (A.  Br.)  Morong. 

AT.  Indica,  Willd.  var.  gracillima,  A.  Br.  by    Engclmann   in    A. 

Gray,  Man.  Ed.  5,  68 1  (1868). 

Stems  almost  capillary,  6-15  inches  high,  much  branched,  the 
branches  alternate ;  the  whole  aspect  of  the  plant  very  graceful. 
Leaves  numerous,  opposite  or  often  fascicled,  3-5  or  more  in  the 
bundle,  setaceous,  ]/2-2  inches  long,  usually  with  about  20  minute 
teeth  on  each  margin.  The  marginal  teeth  are  erect,  with  i -celled 
yellowish  spiny  tips  as  in  the  other  species,  buttressed  by  2,  some- 
times 3  cells  on  the  basal  protuberance  which  give  them  the  aspect 
of  being  3  or  more  celled.  Sheaths  auricled,  with  6  or  7  teeth 
on  each  auricle,  the  teeth  standing  upon  setaceous  divisions  of  the 
sheath.  Dioecious.  Styles  bifid,  the  2  stigmas  very  short.  Fruit 
oblong  cylindrical,  about  ^  line  long  by  */£  line  in  diameter, 
slightly  curved  inwardly,  the  pericarp  straw-colored  or  often  pur- 
plish, marked  by  about  25  rows  of  irregularly  oblong  reticulations; 
seed  not  shining. 

This  plant  differs  very  decidedly  from  N.  Indica,  of  which  Braun 
made  it  a  variety.  It  has  more  slender  and  longer  leaves,  smaller 
and  fewer  teeth,  and  different  fruit  from  that  of  N.  Indica,  which  is 
described  as  ovate.  It  has  sometimes  been  called  N.  minor,  a 
very  different  species,  which  is  not  known  to  occur  in  this  country. 

In  pools  and  ponds,  still  water,  Ashland,  Worcester,  Winches- 
ter and  Stoneham,  Mass.  (Boott,  Morong);  Albany,  New  York 
(Peck) ;  Woodstown,  New  Jersey  (Commons).  Tidal  mud  of  the 
Delaware,  Camden,  New  Jersey,  and  Bristol,  Pa.  (Porter);  Missouri 
(Engelmann.)  (Plate  LXVIII.) 

8.  ZOSTERA,  L.  Sp.  PI.  968  (1753). 

Marine  plants  with  slender  rhizomes  which  root  at  the  joints. 
Stems  branching,  compressed.  Leaves  distichous,  sheathing  at  the 
base,  the  sheaths  stipuliform,  with  inflexed  margins.  Spadix  linear, 
contained  in  a  spathe  which  is  merely  a  sheath  with  overlapping 
flaps  in  the  lower  part  of  a  leaf,  or,  as  some  botanists  prefer  to  say, 
the  spathe  is  on  a  long  peduncle  and  has  a  long  foliaceous  ap- 
pendage at  the  top.  Upon  the  spadix  the  two  kinds  of  flowers 
are  arranged  alternately  in  two  rows.  Sterile  flower  merely  an 
anther  attached  to  the  spadix  near  its  apex,  i-celled,  opening 


62 

irregularly  on  the  ventral  side ;  pollen  threadlike.  Fertile  flower 
fixed  on  the  back  near  the  middle ;  ovary  attenuate  into  a  style  as 
long  as  itself;  stigmas  2,  capillary.  Mature  carpels  flask-shaped, 
membranaceous,  rupturing  irregularly,  beaked  by  the  persistent 
style.  Seeds  ribbed,  the  ribs  showing  through  the  dried  pericarp, 
enclosed  in  a  firm  membranaceous  test;  embryo  thick,  ellipsoidal, 
the  cotyledonary  end  contained  in  a  longitudinal  furrow. 

Species  5  or  6,  natives  of  temperate  seas  throughout  the  world. 
Of  these  3  are  found  on  the  North  American  coast. 

I.    ZOSTERA  MARINA,  L.       Sp.  PL  968  (l753). 

Leaves  ribbon-lrke,  obtuse  at  the  apex,  1-5  feet  or  more  long 
and  1-4  lines  wide,  having  3-7  principal  nerves  and  many  fine 
ones  between  them,  the  nerves  often  obscure.  The  sterile  plants 
are  generally  larger  and  more  vigorous  than  the  fertile.  Spadix 
2^-2 1^  inches  long ;  flowers  about  3  lines  in  length,  crowded, 
varying  greatly  in  the  proportionate  number  of  each  kind,  and 
from  10  to  20  of  each.  Sometimes  the  anthers  are  arranged 
obliquely  in  2's  and  3's.  Ovaries  somewhat  vermiform.  At 
anthesis  the  stigmas  are  thrust  through  the  opening  of  the  spathe 
and  drop  off  before  the  anthers  on  the  same  spadix  open,  showing 
that  they  are  fertilized  by  pollen  from  other  plants.  The  anthers 
at  the  time  of  anthesis  work  themselves  out  of  the  spathe  and  dis- 
charge the  sticky,  stringy  pollen  in  the  water,  thus  leaving  the 
ovaries  by  themselves,  which  then  appear  regularly  disposed  in 
two  rows.  Seeds  cylindrical,  strongly  2O-ribbed,  about  il/2  lines 
long  and  y2  line  in  diameter,  truncate  at  both  ends.  The  ribs 
show  very  clearly  on  the  pericarp. 

The  plant  described  under  the  name  Z.  Orcgana,  by  Dr.  S. 
Watson  in  Proc.  Am.  Ac.  26.  131  (1891),  was  founded  upon  a 
single  specimen  in  the  Gray  Herb.,  collected  by  Hall  in  Oregon  in 
1871.  A  careful  examination  of  this  shows  that  it  is  only  our 
common  Z.  marina.  The  only  substantial  points  on  which  Mr. 
Watson  relies  to  establish  the  species  are  the  long  straight  beak  of 
the  fruit  and  the  lack  of  a  foliar  appendage  on  the  spathe.  The 
beak  is  characteristic  of  all  Zostera  fruit,  and  the  single  spathe  on 
Hall's  specimen  has  the  appendage  broken  off,  as  the  jagged  edges 
seen  under  a  lens  distinctly  show.  I  have  seen  scores  of  them  in 


tf8 

dried  specimens  broken  off  in  the  same  way.     In  every  other  re- 
spect the  plant  is  Z.  marina. 

This  species  is  common  in  sheltered  bays  and  marsh  ditches 
between  high  and  low  water  mark  along  the  Atlantic  coast  from 
Greenland  to  Florida,  and  on  the  Pacific  coast  from  Alaska  to 
California.  Europe  and  Asia.  (Plate  LXIX.) 

2.  ZOSTERA  MINOR  (Cavol.)  Nolte,  in  Reich.  Ic.  vii.  2  (1845). 
Phucagrostis  minor,  Cavol.  Phuc.  Th.  Anth.  xiv.  (1792). 

Z.  nana,  Roth,  Enum.  PI.  Germ.  p.  8  (1827). 

A  specimen  which  probably  belongs  to  this  species,  collected 
at  Key  West,  Florida,  by  Blodgett  is  in  the  Torrey  Herb.  Leaves 
3-6  inches  long,  scarcely  ^  of  a  line  wide,  I -nerved.  It  lacks  fruit, 
however,  to  make  its  rank  sure.  The  seeds  of  this  species  in 
English  specimens  are  about  ^  of  a  line  long,  and  smooth  or  very 
faintly  striate,  only  4  or  5  maturing  in  the  spathe.  (Plate  LXX.) 

3.  ZOSTERA  LATIFOLIA,  Morong. 

Z.  marina,  L.  var.  (?)  latifolia,  Morong,  Bull.  Torr.  Club,  xiii,   160 

(1886). 
Z.  Pacifica,  S.  Watson,  Proc.  Am.  Ac.  26,  131  (1891). 

Rootstocks  very  thick,  sending  up  a  stout  stem  which  is  some- 
times 8  or  10  feet  in  length.  Leaves  2-4  feet  long,  3-6  lines 
wide,  the  broadest  having  from  10  to  13  nerves  and  7  or  8  striae 
between  each  pair  of  nerves.  Spadices  2-3  inches  in  length. 
Fruit  1^2-2  lines  long  by  about  I  line  in  diameter,  cylindrical, 
with  a  straight  beak  as  long  as  itself  and  attached  to  the  spadix 
by  a  short  stipe,  distinctly  20-25  costate.  Pericarp  membranaceous, 
splitting  regularly  along  the  face,  the  ribs  of  the  seed  marked  upon 
the  pericarp  in  the  dried  specimens. 

Puget  Sound  (Nevins);  Santa  Barbara,  Cal.  (Mrs.  R.  F.  Bing- 
ham);  Bolinas  Bay  (Prof.  E.  L.  Greene).  Monterey  (Dr.  C.  L. 
Anderson).  (Plate  LXXI.) 

9.  PHYLLOSPADIX,  Hook.  Fl.  Bor.  Am.  ii.  171  (between  1834 

and  1840). 

Submerged  marine  plants  with  thickened  rootstocks,  sending 
up  slender  stems  which  bear  the  inflorescence  at  the  summit  or 
in  clusters  along  the  upper  part.  Leaves  linear,  grass-like,  sub- 


(54 

coriaceous,  sheathing.  Flowers  dioecious,  in  spathes  like  those  of 
Zostera.  Spathes  with  membranous  edges,  the  back  thickened 
and  terminating  in  long,  leaf-like  appendages.  Spadix  with  a 
series  of  short,  dilated,  foliaceous  flaps,  which  close  over  the 
flowers,  spreading  open  at  maturity.  Sterile  flowers  of  numerous 
sessile  stamens,  in  two  rows  lying  obliquely  crowded  against  each 
other,  i -celled,  dehiscing  by  a  ventral  slit,  dorsally  attached  near 
one  side  about  half-way  up ;  pollen  thread-like.  Fertile  flowers  of 
sessile  ovaries,  attached  above  the  base,  attenuate  into  a  short 
style;  stigmas  2,  capillary;  ovules  pendulous,  orthotropous.  Fruit 
coriaceous,  indehiscent,  beaked  by  the  short  persistent  style,  cor- 
date-sagittate, projecting  at  base  into  2  recurved  wings  or  lobes, 
and  attached  to  the  spadix  between  them.  Seeds  globose,  with 
a  thick,  membranous  test;  embryo  thick,  the  radicular  end 
flattened  ovoid,  the  cotyledonary  end  cylindraceous  and  curved 
upon  the  radicle. 

Two  species  only  are  known,  occurring  upon  the  Pacific  coast ; 
also  on  the  Asiatic  coast. 

i.  PHYLLOSPADIX   TORREYI,  S.  Watson,  Proc.  Am.  Ac.  xiv.  303 

(1879). 

Rootstock  usually  covered  with  the  fibrillose  remains  of  old 
leaves.  Stems  slender,  flat,  20  or  more  inches  in  height,  bearing 
the  spathes  in  clusters  along  the  upper  part.  Leaves  3-6  feet  in 
length,  ^-^  line  wide,  thick,  opaque,  smooth,  obscurely  1-3 
nerved,  blackening  in  drying ;  sheaths  very  long  with  narrow, 
whitish,  membranous  edges.  Spathes  2  or  3  in  a  cluster,  1-2 
inches  long,  slightly  curved,  with  broad,  whitish  membranous 
edges,  each  spathe  on  a  peduncle  l/2-i  inch  in  length.  Append- 
ages of  the  fruiting  spadix  elliptical,  those  of  the  sterile  oblong- 
ovate,  both  obtuse.  Stamens  cylindraceous,  obtuse  at  both  ends. 
Ovaries  flask-shaped,  in  fruit  laterally  flattened  and  carinate  on  the 
back,  about  3  lines  long.  Stigmas  long,  thrust  out  of  the  spathe 
at  anthesis.  Test  reddish,  somewhat  shining. 

Growing  on  rocks  which  are  uncovered  at  low  tide. 

Santa  Barbara,  Cal.  (Mrs.  R.  F.  Bingham);  Los  Angeles  (Parish 
Brothers);  Bolinas  Bay  (Prof.  E.  L.  Greene).  July-August.  (Plate 
LXXII  and  LXXIV.) 


65 

2.  PHYLLOSPADIX  SCOULERI,  Hook.   Fl.   Bor.  Am.  ii.   171,  t.    186 

(before  1840). 

Stems  very  short,  an  inch  or  two  in  height,  bearing  solitary 
spathes.  Leaves  3-6  feet  long,  1-2  lines  wide,  3  nerved,  with 
many  fine  striae  between  the  nerves.  Spadix  appendages  on  both 
kinds  of  flowers  elliptical,  y2  inch  long.  Fruit  broadly  flattened, 
the  lobes  half  as  long  as  the  body.  In  general  appearance  and 
inflorescense  this  is  similar  to  the  preceding  species,  but  may  be 
distinguished  by  its  broader  leaves,  and  especially  by  its  short 
stems  and  single  spathes. 

Barclay  Sound,  Vancouver's  Island  (Macoun);  Tilamook  Head, 
Oregon  (Henderson);  Dundas  Island,  Columbia  River,  Oregon 
(Scouler).  Russian  River,  Siberia  (Ruprecht).  (Plates  LXXIII 
and  LXXIV.) 

Since  the  sheets  of  this  monograph  went  to  press,  I  have  re- 
ceived specimens  of  Potamog e ton  folio sus  var.  Niagarensis,  collected 
by  Mr.  C.  F.  Wheeler  in  Cedar  River,  on  the  grounds  of  the  Agri- 
cultural College  in  Michigan. 

Also  P.  nttilus,  Wolfg.,  collected  by  the  same  gentleman  in  the 
Detroit  River,  July  19,  1892. 

Of  the  following  plates  a  part  were  prepared  by  the  author  for 
another  work,  and  are  here  used  by  permission. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE    XX. 


TRIGLOCHIN   PALUSTRIS,   L. 


MEMOIRS  TORREY  BOTANICAL  CLUB.— PLATE  XXI. 


TRIGLOCHIN   STRIATA,    R.    &   P. 


MEMOIRS   TORREY   BOTANICAL   CLUB.— PLATE   XXII. 


TRIGLOCHIN   MARITIMA.    L. 


MEMOIRS  TORREY  BOTANICAL  CLUB.— PLATE   XXIII. 


SCHEUCHZERIA   PALUSTRIS,   L. 


MEMOIRS  TORREY   BOTANICAL   CLUB.— PLATE   XXIV. 


LIL^EA  SUBULATA,    H.   &   B. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE  XXV. 


POTAMOGETON   NATANS.    L. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   XXVI. 


POTAMOGETON   OAKESIANUS,    ROBBINS. 


MEMOIRS  TORREY  BOTANICAL  CLUB —PLATE   XXVII. 


POTAMOGETON   AMPLIFOLIUS,   TUCKERM. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE  XXVIII. 


POTAMOGETON    PULCHER,    TUCKERM. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   XXIX. 


POTAMOGETON   NUTTALLII.    C.    &   S. 


MEMOIRS  TORREY   BOTANICAL   CLUB.— PLATE   XXX. 


POTAMOGETON   ALPINUS,    BALBIS. 


MEMOIRS  TORREY  BOTANICAL  CLUB.— PLATE  XXXI. 


POTAMOGETON    LONCHITES,    TUCKERM. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   XXXII. 


POTAMOGETON   FAXONI,    MORONG. 


MEMOIRS  TORREY  BOTANICAL  CLUB.— PLATE  xxxnf 


POTAMOGETON   MEXICANUS,    A.    BENNETT. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE  XXXIV. 


POTAMOGETON    HETEROPHYLLUS,    SCHREB. 


MEMOIRS  TORREY   BOTANICAL  CLUB.-PLATE   XXXV. 


POTAMOGETON   SPATHUL^EFORMIS  (ROBBINS)  MORONG. 


MEMOIRS   TORREY   BOTANICAL  CLUB.— PLATE   XXXVI. 


POTAMOGETON   ILLINOENSIS,   MORONG. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE  XXXVII. 


POTAMOGETON  ANGUSTIFOLIUS,   BERCH.    &  PRESL. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE  XXXVIII. 


POTAMOGETON   LUCENS,    L. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   XXXIX. 


POTAMOGETON    PR^ELONGUS,   WULF. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   XL. 


POTAMOGETON   PERFOLIATUS,    L. 


MEMOIRS  TORREY  BOTANICAL  CLUB.— PLATE  XLI. 


POTAMOGETON   MYSTICUS,    MORONG. 


MEMOIRS  TORREY  BOTANICAL  CLUB.— PLATE  XLII 


POTAMOGETON   CONFERVOIDES     REICHENB. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE  XLI1I. 


POTAMOGETON   CURTISSII,    MORONG. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE  XLIV 


POTAMOGETON   CRISPUS,   L. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   XLV. 


POTAMOGETON   ZOSTER^FOLIUS,   SCHUM. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE  XLVI. 


POTAMOGETON   HILLII,   MORONG. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE  XLVI1. 


POTAMOGETON   FOLIOSUS,    RAF. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   XLVIII. 


POTAMOGETON   OBTUSIFOL1US,   M.    AND   K. 


MEMOIRS  TORREY   BOTANICAL   CLUB.— PLATE   XLIX. 


POTAMOGETOX    MAJOR  (FRIES)   MORONG. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   L. 


POTAMOGETON   RUTILUS,   WOLFG. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   LI. 


TOTAMOGETON  VASEYI,   ROBBINS. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   LII. 


POTAMOGETON   LATERALIS,    MORONG. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   LIU. 


POTAMOGETON   PUSILLUS,   L. 


MEMOIRS   TORREY   BOTANICAL  CLUB.— PLATE   LIV. 


POTAMOGETON   GEMMIPARUS  (ROBBINS)  MORONG. 


MEMOIRS   TORREY   BOTANICAL   CLUB.— PLATE   LV. 


POTAMOGETON    DIVERSIFOLIUS,    RAF. 


MEMOIRS  TORREY   BOTANICAL   CLUB.— PLATE   LVI. 


POTAMOGETON   SPIRILLUS,  TUCKERM. 


MEMOIRS  TORREY  BOTANICAL  CLUB.— PLATE   LVII. 


POTAMOGETON   FILIFORMIS,   PERS. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   LVIII. 


POTAMOGETON    PECTINATUS,    L. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE    LIX. 


POTAMOGETON    LATIFOLIUS  (ROBBINS)   MORONG 


MEMOIRS   TORREY   BOTANICAL   CLUB.— PLATE   LX 


POTAMOGETON    INTERRUPTUS,    KIT. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE  LXI. 


POTAMOGETON   ROBBINSII,   OAKES. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   LXII. 


RUPPIA   MARITIMA.    L. 


MEMOIRS  TORREY  BOTANICAL  CLUB.— PLATE   LXIII. 


RUPPIA   OCCIDENTALS,    S.    WATSON. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   LXIV. 


ZANNICHELLIA  PALUSTRIS,    L. 


MEMOIRS  TORREY   BOTANICAL  CLUB —PLATE   LXV. 


NAIAS   MARINA,    L. 


MEMOIRS  TORREY   BOTANICAL   CLUB.— PLATE    LXVI. 


NAIAS   FLEXILIS  (WILLD.)  ROSTK.   AND  SCHM. 


MEMOIRS  TORREY   BOTANICAL   CLUB.— PLATE    LXVII. 


A 


NAIAS   GUADALUPENSIS  (SPRENG.)   MORONG. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   LXVIII. 


NAIAS  GRACILLIMA  (A.    BR.)   MORONG. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   LXIX. 


ZOSTERA  MARINA,    L. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   LXX. 


NAIAS  MINOR  (CAVOL)  NOLTE. 


MEMOIRS  TORREY    BOTANICAL   CLUB.— PLATE   LXXI. 


ZOSTERA    LATIFOLIA,    MORONG. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   LXXII. 


PHYLLOSPADIX  TORREYI,    S.    WATSON. 


MEMOIRS  TORREY   BOTANICAL  CLUB.— PLATE   LXXIII. 


PHYLLOSPADIX  SCOULERI,    HOOK. 


MEMOIRS  TORREY  BOTANICAL  CLUB.— PLATE   LXXIV. 


PISTILS,   SPADIX  AND   FRUITS  OF  PHYLLOSPADIX. 
i,  2.    P.  SCOULERI.  3,  4.  5-    V.  TORREYI. 


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